Extragalactic Planetary Nebulae: Observational Challenges & Future Prospects

The study of extragalactic planetary nebulae (EPN) is a rapidly expanding field. The advent of powerful new instrumentation such as the PN spectrograph has led to an avalanche of new EPN discoveries both within and between galaxies. We now have thousands of EPN detections in a heterogeneous selection of nearby galaxies and their local environments, dwarfing the combined galactic detection efforts of the last century. Key scientific motivations driving this rapid growth in EPN research and discovery have been the use of the PNLF as a standard candle, as dynamical tracers of their host galaxies and dark matter and as probes of Galactic evolution. This is coupled with the basic utility of PN as laboratories of nebula physics and the consequent comparison with theory where population differences, abundance variations and star formation history within and between stellar systems informs both stellar and galactic evolution. Here we pose some of the burning questions, discuss some of the observational challenges and outline some of the future prospects of this exciting, relatively new, research area as we strive to go fainter, image finer, see further and survey faster than ever before and over a wider wavelength regimeComment: 4 pages, no figures, LaTeX, to be published in Proceedings of the ESO workshop on Planetary Nebulae beyond the Milky Way held at ESO, Garching, May 19-21, 200

Spectral theory and time asymptotics of size-structured two-phase population models

This work provides a general spectral analysis of size-structured two-phase population models. Systematic functional analytic results are given. We deal first with the case of finite maximal size. We characterize the irreducibility of the corresponding $L^{1}$ semigroup in terms of properties of the different parameters of the system. We characterize also the spectral gap property of the semigroup. It turns out that the irreducibility of the semigroup implies the existence of the spectral gap. In particular, we provide a general criterion for asynchronous exponential growth. We show also how to deal with time asymptotics in case of lack of irreducibility. Finally, we extend the theory to the case of infinite maximal size.Comment: 36 page

Central Stars of Planetary Nebulae in Galactic Open Clusters: Providing additional data for the White Dwarf Initial-to-Final-Mass Relation

Accurate (<10%) distances of Galactic star clusters allow precise estimation of the physical parameters of any physically associated Planetary Nebula (PN) and also that of its central star (CSPN) and its progenitor. The progenitor's mass can be related to the PN's chemical characteristics and furthermore, provides additional data for the widely used white dwarf (WD) initial-to-final mass relation (IFMR) that is crucial for tracing the development of both carbon and nitrogen in entire galaxies. To date there is only one PN (PHR1315- 6555) confirmed to be physically associated with a Galactic open cluster (ESO 96 -SC04) that has a turn-off mass $\sim$2 M$_{\odot}$. Our deep HST photometry was used for the search of the CSPN of this currently unique PN. In this work, we present our results.Comment: 2 pages, 1 figure, IAU343 Synposiu

Benchmarking for Fisheries Governance

The paper develops a benchmarking framework to improve fisheries governance and promote resilient ecosystems and profitable fisheries. The benchmarking includes five key components: accountability; transparency; incentives; risk assessment and management; and adaptability. Collectively, these factors provide a framework to benchmark and improve fisheries governance. Initial findings from benchmarking in two of Australia's Commonwealth fisheries indicate that the framework provides an important tool to help overcome the underlying causes of unsustainability in capture fisheries - poor and/or ineffective fisheries governance.fisheries, governance, sustainability

Challenges and Opportunities for Catholic Schools Globally: Insights from OIEC\u27s World Congress

Every four years, the International Office of Catholic Education (OIEC in French) organizes its World Congress as an opportunity for participants — including school teachers and principals, to share their experiences and achievements, as well as the challenges they face. In June 2019, the Educatio Si Congress took place in New York in partnership with Fordham University. The theme of the Congress was “Educating to fraternal humanism to build a civilization of love.” The closing plenary was held at the United Nations to highlight the contribution of Catholic schools to the fourth Sustainable Education Goal (SDG4), namely ensuring inclusive and equitable quality education and promoting lifelong learning opportunities for all. This symposium comprises of selected contributions made at the congress, with a focus on the opening plenary at the Church of St Paul the Apostle and the closing plenary at the United Nations

The Unusual Variability of the Large Magellanic Cloud Planetary Nebula RPJ 053059-683542

We present images and light curves of the bipolar Planetary Nebula RPJ 053059-683542 that was discovered in the Reid-Parker AAO/UKST H-alpha survey of the Large Magellanic Cloud (LMC). The emission from this object appears entirely nebular, with the central star apparently obscured by a central band of absorption that bisects the nebula. The light curves, which were derived from images from the SuperMACHO project at CTIO, showed significant, spatially resolved variability over the period 2002 January through 2005 December. Remarkably, the emission from the two bright lobes of the nebula vary either independently, or similarly but with a phase lag of at least one year. The optical spectra show a low level of nebular excitation, and only modest N enrichment. Infrared photometry from the 2MASS and SAGE surveys indicates the presence of a significant quantity of dust. The available data imply that the central star has a close binary companion, and that the system has undergone some kind of outburst event that caused the nebular emission to first brighten and then fade. Further monitoring, high-resolution imaging, and detailed IR polarimetry and spectroscopy would uncover the nature of this nebula and the unseen ionizing source.Comment: Accepted for ApJ Letters; 6 page

Dynamic State Estimation in Distributed Aircraft Electric Control Systems via Adaptive Submodularity

International audienceWe consider the problem of estimating the discrete state of an aircraft electric system under a distributed control architecture through active sensing. The main idea is to use a set of controllable switches to reconfigure the system in order to gather more information about the unknown state. By adaptively making a sequence of reconfiguration decisions with uncertain outcome, then correlating measurements and prior information to make the next decision, we aim to reduce the uncertainty. A greedy strategy is developed that maximizes the one-step expected uncertainty reduction. By exploiting recent results on adaptive submodularity, we give theoretical guarantees on the worst-case performance of the greedy strategy. We apply the proposed method in a fault detection scenario where the discrete state captures possible faults in various circuit components. In addition, simple abstraction rules are proposed to alleviate state space explosion and to scale up the strategy. Finally, the efficiency of the proposed method is demonstrated empirically on different circuits