A catalogue of cataclysmic variables from 20 years of the Sloan Digital Sky Survey with new classifications, periods, trends and oddities

We present a catalogue of 507 cataclysmic variables (CVs) observed in SDSS I to IV including 70 new classifications collated from multiple archival data sets. This represents the largest sample of CVs with high-quality and homogeneous optical spectroscopy. We have used this sample to derive unbiased space densities and period distributions for the major sub-types of CVs. We also report on some peculiar CVs, period bouncers and also CVs exhibiting large changes in accretion rates. We report 70 new CVs, 59 new periods, 178 unpublished spectra and 262 new or updated classifications. From the SDSS spectroscopy, we also identified 18 systems incorrectly identified as CVs in the literature. We discuss the observed properties of 13 peculiar CVS, and we identify a small set of eight CVs that defy the standard classification scheme. We use this sample to investigate the distribution of different CV sub-types, and we estimate their individual space densities, as well as that of the entire CV population. The SDSS I to IV sample includes 14 period bounce CVs or candidates. We discuss the variability of CVs across the Hertzsprung-Russell diagram, highlighting selection biases of variability-based CV detection. Finally, we searched for, and found eight tertiary companions to the SDSS CVs. We anticipate that this catalogue and the extensive material included in the Supplementary Data will be useful for a range of observational population studies of CVs.Comment: Submitted to MNRAS. Supplementary information available at https://warwick.ac.uk/fac/sci/physics/research/astro/people/keithinight/sdss_paper_supplementary_informatio

The age-metallicity relation in the solar neighbourhood from a pilot sample of white dwarf-main sequence binaries

The age-metallicity relation (AMR) is a fundamental observational constraint for understanding how the Galactic disc formed and evolved chemically in time. However, there is not yet an agreement on the observational properties of the AMR for the solar neighbourhood, primarily due to the difficulty in obtaining accurate stellar ages for individual field stars. We have started an observational campaign for providing the much needed observational input by using wide white-dwarf-main-sequence (WDMS) binaries. White dwarfs are `natural' clocks and can be used to derive accurate ages. Metallicities can be obtained from the main-sequence companions. Since the progenitors of white dwarfs and the main-sequence stars were born at the same time, WDMS binaries provide a unique opportunity to observationally constrain in a robust way the properties of the AMR. In this work we present the AMR derived from analysing a pilot sample of 23 WDMS binaries and provide clear observational evidence for the lack of correlation between age and metallicity at young and intermediate ages (0-7 Gyr)

The age–metallicity relation in the solar neighbourhood from a pilot sample of white dwarf–main sequence binaries

The age–metallicity relation (AMR) is a fundamental observational constraint for understanding how the Galactic disc formed and evolved chemically in time. However, there is not yet an agreement on the observational properties of the AMR for the solar neighbourhood, primarily due to the difficulty in obtaining accurate stellar ages for individual field stars. We have started an observational campaign for providing the much needed observational input by using wide white-dwarf–main-sequence (WDMS) binaries. White dwarfs are ‘natural’ clocks and can be used to derive accurate ages. Metallicities can be obtained from the main-sequence companions. Since the progenitors of white dwarfs and the main-sequence stars were born at the same time, WDMS binaries provide a unique opportunity to observationally constrain in a robust way the properties of the AMR. In this work we present the AMR derived from analysing a pilot sample of 23 WDMS binaries and provide clear observational evidence for the lack of correlation between age and metallicity at young and intermediate age

Minimizing Shape Change at Zn Sponge Anodes in Rechargeable Ni-Zn Cells: Impact of Electrolyte Formulation

The historically poor electrochemical rechargeability of Zn in alkaline electrolyte has hindered the commercial viability of Ni-Zn batteries, a system otherwise of interest because of high specific energy (up to 140 Wh kg -1 ). We have redesigned the Zn anode as a three-dimensional (3D), monolithic porous architecture ("sponge") that exhibits unprecedented Zn specific capacity and dendrite-free cycling. Maintaining the integrity of the 3D Zn sponge architecture throughout charge-discharge is required to ultimately achieve technologically relevant performance in terms of cycle life and capacity. En route to this goal, we systematically evaluated a series of electrolyte and electrode additives used in conjunction with our Zn sponge anode in order to down-select formulations that minimize electrode shape change with cycling in prototype Ni-3D Zn cells. The classes of additives chosen for this study include those that either inhibit ZnO passivation during discharge (Type I: LiOH, K 2 SiO 3 ) or promote it (Type II/III: KF, K 2 CO 3 , ZnO, Ca(OH) 2 ), as well as combinations thereof. We find that the second class of additives effectively retains the cycled Zn sponge in its pre-cycled condition. Nickel-zinc (Ni-Zn) batteries exhibit high practical specific energies (up to 140 Wh kg -1 ) and operate using earth-abundant active materials and nonflammable aqueous electrolytes. The Zn electrode has a high theoretical specific capacity (820 mAh g -1 ) and depending on the target depth-of-discharge at the Zn (DOD Zn ), Ni-Zn batteries are an attractive competitor to Pb-acid, Ni-metal hydride, and Li-ion batteries. Despite these advantages, the historically poor rechargeability of the Zn electrode has hindered the Ni-Zn system from contending in the consumer marketplace. While examples of commercial secondary Ni-Zn batteries exist (e.g., Battery Power International (BPI) and PowerGenix), they remain plagued by limited cycle life and inconsistency in meeting manufacturer-specified capacity. 1 Until recently, the prevailing method to enhance the cycle life of Zn-based batteries (Ni-Zn, Ag-Zn, Zn-MnO 2 ) focused on the use of additives in the electrolyte and/or incorporated into the electrode structure to mitigate the formation of short-inducing dendrites at the Zn anode. This approach has been modestly successful, 2,3,4,5 yet the lack of a competitive commercial Ni-Zn battery with long cycle life suggests that further advances beyond reliance on additives is required. In response to this challenge, we have redesigned the Zn anode as a three-dimensional (3D), monolithic, aperiodic porous Zn architecture ("sponge"). Additives for Zn-based batteries can be classified into three distinct types: r "Type I" electrolyte additives that prevent ZnO passivation of the electrode by suppressing supersaturation of zincate anions (Z

Resolving the ancestry of Austronesian-speaking populations

There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The “out-of-Taiwan” model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion

Investigation of phase transformations and corrosion resistance in Co/CoCo2O4 nanowires and their potential use as a basis for lithium-ion batteries

The paper is devoted to the study of the effect of thermal annealing on the change in the structural properties and phase composition of metal Co nanostructures, as well as the prospects of their use as anode materials for lithium-ion batteries. During the study, a four-stage phase transition in the structure of nanowires consisting of successive transformations of the structure (Со-FCC/Co-HCP) → (Со-FCС) → (Со-FCC/СоСо2О4) → (СоСо2О4), accompanied by uniform oxidation of the structure of nanowires with an increase in temperature above 400 °C. In this case, an increase in temperature to 700 °C leads to a partial destruction of the oxide layer and surface degradation of nanostructures. During life tests, it was found that the lifetime for oxide nanostructures exceeds 500 charge/discharge cycles, for the initial nanostructures and annealed at a temperature of 300 °С, the lifetimes are 297 and 411 cycles, respectively. The prospects of using Co/CoCo2O4 nanowires as the basis for lithium-ion batteries is shown. © 2019, The Author(s)

Global assessment of marine plastic exposure risk for oceanic birds

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species

Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis

Funding GMP, PN, and CW are supported by NHLBI R01HL127564. GMP and PN are supported by R01HL142711. AG acknowledge support from the Wellcome Trust (201543/B/16/Z), European Union Seventh Framework Programme FP7/2007–2013 under grant agreement no. HEALTH-F2-2013–601456 (CVGenes@Target) & the TriPartite Immunometabolism Consortium [TrIC]-Novo Nordisk Foundation’s Grant number NNF15CC0018486. JMM is supported by American Diabetes Association Innovative and Clinical Translational Award 1–19-ICTS-068. SR was supported by the Academy of Finland Center of Excellence in Complex Disease Genetics (Grant No 312062), the Finnish Foundation for Cardiovascular Research, the Sigrid Juselius Foundation, and University of Helsinki HiLIFE Fellow and Grand Challenge grants. EW was supported by the Finnish innovation fund Sitra (EW) and Finska Läkaresällskapet. CNS was supported by American Heart Association Postdoctoral Fellowships 15POST24470131 and 17POST33650016. Charles N Rotimi is supported by Z01HG200362. Zhe Wang, Michael H Preuss, and Ruth JF Loos are supported by R01HL142302. NJT is a Wellcome Trust Investigator (202802/Z/16/Z), is the PI of the Avon Longitudinal Study of Parents and Children (MRC & WT 217065/Z/19/Z), is supported by the University of Bristol NIHR Biomedical Research Centre (BRC-1215–2001) and the MRC Integrative Epidemiology Unit (MC_UU_00011), and works within the CRUK Integrative Cancer Epidemiology Programme (C18281/A19169). Ruth E Mitchell is a member of the MRC Integrative Epidemiology Unit at the University of Bristol funded by the MRC (MC_UU_00011/1). Simon Haworth is supported by the UK National Institute for Health Research Academic Clinical Fellowship. Paul S. de Vries was supported by American Heart Association grant number 18CDA34110116. Julia Ramierz acknowledges support by the People Programme of the European Union’s Seventh Framework Programme grant n° 608765 and Marie Sklodowska-Curie grant n° 786833. Maria Sabater-Lleal is supported by a Miguel Servet contract from the ISCIII Spanish Health Institute (CP17/00142) and co-financed by the European Social Fund. Jian Yang is funded by the Westlake Education Foundation. Olga Giannakopoulou has received funding from the British Heart Foundation (BHF) (FS/14/66/3129). CHARGE Consortium cohorts were supported by R01HL105756. Study-specific acknowledgements are available in the Additional file 32: Supplementary Note. The views expressed in this manuscript are those of the authors and do not necessarily represent the views of the National Heart, Lung, and Blood Institute; the National Institutes of Health; or the U.S. Department of Health and Human Services.Peer reviewedPublisher PD

Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis

Publisher Copyright: © 2022, The Author(s).Background: Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery. Results: To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N = 1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3–5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism. Conclusions: Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.Peer reviewe