104 research outputs found

    Neolithic dispersal implications of murids from late Holocene archaeological and modern natural deposits in the Talaud Islands, northern Sulawesi

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    The Sangihe-Talaud Archipelago represents a group of 77 remote islands located between the Philippines and North Sulawesi, in the northern sector of Wallacea. The Talaud Islands have a rich and significant archaeological record going back to the Pleistocene and are instrumental in understanding Pleistocene colonisation of small islands and later models of Austronesian language dispersal. Here we report on vertebrate material excavated from Leang Mande'et, a late Holocene rockshelter on Karakelang, the main island in the Talaud group. The site represents a periodically occupied shelter used for gardening. Fauna recovered predominately comprises murid elements, with at least four taxa (Rattus rattus, Rattus exulans and two Melomys species) found. The rodents show clear signs of being deposited by raptors rather than humans, unlike the small number of fish remains also recovered. DNA sequences from several Rattus rattus specimens are referrable to Rattus rattus complex lineage IV, a lineage with a southern Indochinese origins and broad modern representation through Indonesia and the Philippines. The lack of any Rattus rattus complex lineage II from Leang Mande’et suggests that the first agricultural inhabitants of this island did not come from Taiwan or northern Indochina, but rather that they either originated from the south or that, once established in the Talauds, opened up significant trade networks to the south and in the process acquired a significant pest

    A new species of Rattus (Rodentia: Muridae) from Manus Island, Papua New Guinea

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    We describe a new species of Rattus, from 3 modern specimens collected on Manus Island in the Admiralty Group, Papua New Guinea, between 2002 and 2012. Subfossil specimens of early to late Holocene age from the Pamwak archaeological site on Manus Island are referred to the new species on morphological criteria; these confirm the species as a long-term resident of Manus Island. The new species is distinguished by its combination of large size; short tail; dorsal pelage that is coarse, spiny, and dark, with prominent black guard hairs; and sharply contrasting cream ventral pelage. Based on its overall body form, the species is almost certainly terrestrial. The dentition combines robust incisors with relatively small molars and the cranium displays a distinctive mélange of characters—including an elongate and anteriorly expanded rostrum and a mesopterygoid fossa that is narrow anteriorly and broadens to the rear. Sequence data from the mitochondrial control region and 3 nuclear genes place the new species as a highly divergent member of the Australo–Papuan Rattus radiation, with no identified close relative among sampled taxa. Morphological comparisons are made between the new species and other pertinent species of Rattus from the region, including R. sanila, a species known only from Late Pleistocene fossil to Late Holocene subfossil remains from an archaeological site on New Ireland. The conservation status of the new species is discussed in the light of a recent survey that failed to locate surviving populations in 2 areas of natural forest on Manus Island. Further survey work is urgently needed to identify any surviving populations and to assess the role of potential threats to the species

    First Light And Reionisation Epoch Simulations (FLARES) XI: [OIII] emitting galaxies at 5<z<105<z<10

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    JWST has now made it possible to probe the rest-frame optical line emission of high-redshift galaxies extending to z~9, and potentially beyond. To aid in the interpretation of these emerging constraints, in this work we explore predictions for [OIII] emission in high-redshift galaxies using the First Light and Reionisation Epoch Simulations (FLARES). We produce predictions for the [OIII] luminosity function, its correlation with the UV luminosity, and the distribution of equivalent widths (EWs). We also explore how the [OIII] EW correlates with physical properties including specific star formation rate, metallicity, and dust attenuation. Our predictions are largely consistent with recent observational constraints on the luminosity function, average equivalent widths, and line ratios. However, they fail to reproduce the observed tail of high-EW sources and the number density of extreme line emitters. Possibilities to explain these discrepancies include an additional source of ionising photons and/or greater stochasticity in star formation in the model or photometric scatter and/or bias in the observations. With JWST now rapidly building larger samples and a wider range of emission lines the answer to this remaining discrepancy should be available imminently.Comment: 15 pages, accepted for publication in MNRAS, minor changes from original versio

    Phylogenomics Reveals Ancient Gene Tree Discordance in the Amphibian Tree of Life

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    Molecular phylogenies have yielded strong support for many parts of the amphibian Tree of Life, but poor support for the resolution of deeper nodes, including relationships among families and orders. To clarify these relationships, we provide a phylogenomic perspective on amphibian relationships by developing a taxon-specific Anchored Hybrid Enrichment protocol targeting hundreds of conserved exons which are effective across the class. After obtaining data from 220 loci for 286 species (representing 94% of the families and 44% of the genera), we estimate a phylogeny for extant amphibians and identify gene tree–species tree conflict across the deepest branches of the amphibian phylogeny. We perform locus-by-locus genealogical interrogation of alternative topological hypotheses for amphibian monophyly, focusing on interordinal relationships. We find that phylogenetic signal deep in the amphibian phylogeny varies greatly across loci in a manner that is consistent with incomplete lineage sorting in the ancestral lineage of extant amphibians. Our results overwhelmingly support amphibian monophyly and a sister relationship between frogs and salamanders, consistent with the Batrachia hypothesis. Species tree analyses converge on a small set of topological hypotheses for the relationships among extant amphibian families. These results clarify several contentious portions of the amphibian Tree of Life, which in conjunction with a set of vetted fossil calibrations, support a surprisingly younger timescale for crown and ordinal amphibian diversification than previously reported. More broadly, our study provides insight into the sources, magnitudes, and heterogeneity of support across loci in phylogenomic data sets

    Cosmic Evolution Early Release Science (CEERS) survey: The colour evolution of galaxies in the distant Universe

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    The wavelength-coverage and sensitivity of JWST now enables us to probe the rest-frame UV - optical spectral energy distributions (SEDs) of galaxies at high-redshift (z>4z>4). From these SEDs it is, in principle, through SED fitting possible to infer key physical properties, including stellar masses, star formation rates, and dust attenuation. These in turn can be compared with the predictions of galaxy formation simulations allowing us to validate and refine the incorporated physics. However, the inference of physical properties, particularly from photometry alone, can lead to large uncertainties and potential biases. Instead, it is now possible, and common, for simulations to be \emph{forward-modelled} to yield synthetic observations that can be compared directly to real observations. In this work, we measure the JWST broadband fluxes and colours of a robust sample of 5<z<105<z<10 galaxies using the Cosmic Evolution Early Release Science (CEERS) Survey. We then analyse predictions from a variety of models using the same methodology and compare the NIRCam/F277W magnitude distribution and NIRCam colours with observations. We find that the predicted and observed magnitude distributions are similar, at least at 5858 the distributions differ somewhat, though our observed sample size is small and thus susceptible to statistical fluctuations. Likewise, the predicted and observed colour evolution show broad agreement, at least at 5<z<85<z<8. There is however some disagreement between the observed and modelled strength of the strong line contribution. In particular all the models fails to reproduce the F410M-F444W colour at z>8z>8, though, again, the sample size is small here.Comment: 11 pages, 10 figures, submitted to MNRA

    A recent gibbon ape leukemia virus germline integration in a rodent from New Guinea

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    Germline colonization by retroviruses results in the formation of endogenous retroviruses (ERVs). Most colonization’s occurred millions of years ago. However, in the Australo-Papuan region (Australia and New Guinea), several recent germline colonization events have been discovered . The Wallace Line separates much of Southeast Asia from the Australo-Papuan region restricting faunal and pathogen dispersion. West of the Wallace Line, gibbon ape leukemia viruses (GALVs) have been isolated from captive gibbons. Two microbat species from China appear to have been infected naturally. East of Wallace’s Line, the woolly monkey virus (a GALV) and the closely related koala retrovirus (KoRV) have been detected in eutherians and marsupials in the Australo-Papuan region, often vertically transmitted. The detected vertically transmitted GALV-like viruses in Australo-Papuan fauna compared to sporadic horizontal transmission in Southeast Asia and China suggest the GALV-KoRV clade originates in the former region and further models of early-stage genome colonization may be found. We screened 278 samples, seven bat and one rodent family endemic to the Australo-Papuan region and bat and rodent species found on both sides of the Wallace Line. We identified two rodents ( Melomys ) from Australia and Papua New Guinea and no bat species harboring GALV-like retroviruses. Melomys leucogaster from New Guinea harbored a genomically complete replication-competent retrovirus with a shared integration site among individuals. The integration was only present in some individuals of the species indicating this retrovirus is at the earliest stages of germline colonization of the Melomys genome, providing a new small wild mammal model of early-stage genome colonization

    Remdesivir-ivermectin combination displays synergistic interaction with improved in vitro activity against SARS-CoV-2

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    A key element for the prevention and management of COVID-19 is the development of effective therapeutics. Drug combination strategies of repurposed drugs offer several advantages over monotherapies, including the potential to achieve greater efficacy, the potential to increase the therapeutic index of drugs and the potential to reduce the emergence of drug resistance. Here, we report on the in vitro synergistic interaction between two FDA approved drugs, remdesivir and ivermectin resulting in enhanced antiviral activity against SARS-CoV-2. Whilst the in vitro synergistic activity reported here does not support the clinical application of this combination treatment strategy, due to insufficient exposure of ivermectin in vivo, the data do warrant further investigation. Efforts to define the mechanisms underpinning the observed synergistic action, could lead to the development of novel therapeutic treatment strategies

    Long-term genetic consequences of mammal reintroductions into an Australian conservation reserve

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    Available online 05 January 2018Reintroduction programs aim to restore self-sustaining populations of threatened species to their historic range. However, demographic restoration may not reflect genetic restoration, which is necessary for the long-term persistence of populations. Four threatened Australian mammals, the greater stick-nest rat (Leporillus conditor), greater bilby (Macrotis lagotis), burrowing bettong (Bettongia lesueur) and western barred bandicoot (Perameles bougainville), were reintroduced at Arid Recovery Reserve in northern South Australia over the last 18 years. These reintroductions have been deemed successful based on population growth and persistence, however the genetic consequences of the reintroductions are not known. We generated large single nucleotide polymorphism (SNP) datasets for each species currently at Arid Recovery and compared them to samples collected from founders. We found that average genetic diversity in all populations at the Arid Recovery Reserve are close to, or exceeding, the levels measured in the founders. Increased genetic diversity in two species was achieved by admixing slightly diverged and inbred source populations. Our results suggest that genetic diversity in translocated populations can be improved or maintained over relatively long time frames, even in small conservation reserves, and highlight the power of admixture as a tool for conservation management.Lauren C. White, Katherine E. Moseby, Vicki A. Thomson, Stephen C. Donnellan, Jeremy J. Austi

    Why Has Personality Psychology Played an Outsized Role in the Credibility Revolution?

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    21 pages. Published at PsychOpen: 10.5964/ps.6001Personality is not the most popular subfield of psychology. But, in one way or another, personality psychologists have played an outsized role in the ongoing “credibility revolution” in psychology. Not only have individual personality psychologists taken on visible roles in the movement, but our field’s practices and norms have now become models for other fields to emulate (or, for those who share Baumeister’s (2016, https://doi.org/10.1016/j.jesp.2016.02.003) skeptical view of the consequences of increasing rigor, a model for what to avoid). In this article we discuss some unique features of our field that may have placed us in an ideal position to be leaders in this movement. We do so from a subjective perspective, describing our impressions and opinions about possible explanations for personality psychology’s disproportionate role in the credibility revolution. We also discuss some ways in which personality psychology remains less-than-optimal, and how we can address these flaws
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