1,671 research outputs found

    Biogeography and ecological diversification of a mayfly clade in New Guinea

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    Understanding processes that have driven the extraordinary high level of biodiversity in the tropics is a long-standing question in biology. Here we try to assess whether the large lineage richness found in a New Guinean clade of mayflies (Ephemeroptera), namely the Thraulus group (Leptophlebiidae) could be associated with the recent orogenic processes, by applying a combination of phylogenetic, biogeographic and ecological shift analyses. New Guinean representatives of the Thraulus group appear monophyletic, with the possible exception of a weakly-supported early-diverging clade from the Sunda Islands. Dating analyses suggest an Eocene origin of the Thraulus group, predating by several million years current knowledge on the origin of other New Guinean aquatic organisms. Biogeographic inferences indicate that 27 of the 28 inferred dispersals (96.4%) occurred during the Eocene, Oligocene and Miocene, while only one dispersal (3.6%) took place during the Pliocene-Pleistocene. This result contrasts with the higher number of altitudinal shifts (15 of 22; 68.2%) inferred during the Pliocene-Pleistocene time slice. Our study illustrates the role played by – potentially ecological - diversification along the elevation gradient in a time period concomitant with the establishment of high-altitude ecological niches, i.e., during orogenesis of the central New Guinean mountain range. This process might have taken over the previous main mode of diversification at work, characterized by dispersal and vicariance, by driving lineage divergence of New Guinean Leptophlebiidae across a wide array of habitats along the elevation gradient. Additional studies on organisms spanning the same elevation range as Thraulus mayflies in the tropics are needed to evaluate the potential role of the ecological opportunity or taxon cycles hypotheses in partly explaining the latitudinal diversity gradient

    Quantifying the scale and socioeconomic drivers of bird hunting in Central African forest communities

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    Global biodiversity is threatened by unsustainable exploitation for subsistence and commerce, and tropical forests are facing a hunting crisis. In Central African forests, hunting pressure has been quantified by monitoring changes in the abundance of affected species and by studying wild meat consumption, trade and hunter behaviour. However, a proportion of offtake is also discarded as bycatch or consumed by hunters when working, which can be overlooked by these methods. For example, remains of hornbills and raptors are found regularly in hunting camps but relatively few birds are consumed in households or traded in markets. Hornbill and raptor populations are sensitive to small increases in mortality because of their low intrinsic population growth rates, however, the scale and socioeconomic drivers of the cryptic hunting pressure affecting these species have not been quantified. We used direct and indirect questioning and mixed-effects models to quantify the socioeconomic predictors, scale and seasonality of illegal bird hunting and consumption in Littoral Region, Cameroon. We predicted that younger, unemployed men with low educational attainment (i.e. hunters) would consume birds more often than other demographics, and that relative offtake would be higher than expected based on results from village and market-based studies. We found that birds were primarily hunted and consumed by unemployed men during the dry season but, in contrast to expectations, we found that hunting prevalence increased with educational attainment. Within unemployed men educated to primary level (240 of 675 respondents in 19 villages), we estimated an average of 29 hornbills and eight raptors (compared with 19 pangolins) were consumed per month during the study period (Feb–Jun 2015) in a catchment of c.1135 km2. We conclude that large forest birds face greater hunting pressure than previously recognised, and birds are a regular source of protein for men during unemployment. Offtake levels may be unsustainable for some raptors and hornbills based on life history traits but in the absence of sufficient baseline ecological and population data we recommend that a social-ecological modeling approach is used in future to quantify hunting sustainability

    Evaluation of three 3ABC ELISAs for foot-and-mouth disease non-structural antibodies using latent class analysis

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    BACKGROUND: Foot-and-mouth disease (FMD) is a highly contagious viral disease of even-toed ungulates. Serological diagnosis/surveillance of FMD presents several problems as there are seven serotypes worldwide and in the event of vaccination it may be necessary to be able to identify FMD infected/exposed animals irrespective of their vaccination status. The recent development of non-structural 3ABC protein (NSP) ELISA tests has greatly advanced sero-diagnosis/surveillance as these tests detect exposure to live virus for any of the seven serotypes of FMD, even in vaccinated populations. This paper analyses the performance of three NSP tests using a Bayesian formulation of the Hui-Walter latent class model to estimate test sensitivity and specificity in the absence of a "gold-standard" test, using sera from a well described cattle population in Cameroon with endemic FMD. RESULTS: The analysis found a high sensitivity and specificity for both the Danish C-ELISA and the World Organisation for Animal Health (O.I.E.) recommended South American I-ELISA. However, the commercial CHEKIT kit, though having high specificity, has very low sensitivity. The results of the study suggests that for NSP ELISAs, latent class models are a useful alternative to the traditional approach of evaluating diagnostic tests against a known "gold-standard" test as imperfections in the "gold-standard" may give biased test characteristics. CONCLUSION: This study demonstrates that when applied to naturally infected zebu cattle managed under extensive rangeland conditions, the FMD ELISAs may not give the same parameter estimates as those generated from experimental studies. The Bayesian approach allows for full posterior probabilities and capture of the uncertainty in the estimates. The implications of an imperfect specificity are important for the design and interpretation of sero-surveillance data and may result in excessive numbers of false positives in low prevalence situations unless a follow-up confirmatory test such as the enzyme linked immunoelectrotransfer blot (EITB) is used

    Femtosecond x-ray diffraction from an aerosolized beam of protein nanocrystals

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    We demonstrate near-atomic-resolution Bragg diffraction from aerosolized single granulovirus crystals using an x-ray free-electron laser. The form of the aerosol injector is nearly identical to conventional liquid-microjet nozzles, but the x-ray-scattering background is reduced by several orders of magnitude by the use of helium carrier gas rather than liquid. This approach provides a route to study the weak diffuse or lattice-transform signal arising from small crystals. The high speed of the particles is particularly well suited to upcoming MHz-repetition-rate x-ray free-electron lasers

    Religio-ethical discussions on organ donation among Muslims in Europe: an example of transnational Islamic bioethics

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    This article analyzes the religio-ethical discussions of Muslim religious scholars, which took place in Europe specifically in the UK and the Netherlands, on organ donation. After introductory notes on fatwas (Islamic religious guidelines) relevant to biomedical ethics and the socio-political context in which discussions on organ donation took place, the article studies three specific fatwas issued in Europe whose analysis has escaped the attention of modern academic researchers. In 2000 the European Council for Fatwa and Research (ECFR) issued a fatwa on organ donation. Besides this “European” fatwa, two other fatwas were issued respectively in the UK by the Muslim Law (Shariah) Council in 1995 and in the Netherlands by the Moroccan religious scholar Muṣṭafā Ben Ḥamza during a conference on “Islam and Organ Donation” held in March 2006. The three fatwas show that a great number of Muslim religious scholars permit organ donation and this holds true for donating organs to non-Muslims as well. Further, they demonstrate that transnationalism is one of the main characteristics of contemporary Islamic bioethics. In a bid to develop their own standpoints towards organ donation, Muslims living in the West rely heavily on fatwas imported from the Muslim world

    Angular Diameters of the Hyades Giants Measured with the CHARA Array

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    We present angular diameters of the Hyades giants, gamma, delta^1, epsilon, and theta^1 Tau from interferometric measurements with the CHARA Array. Our errors in the limb-darkened angular diameters for these stars are all less than 2%, and in combination with additional observable quantities, we determine the effective temperatures, linear radii and absolute luminosities for each of these stars. Additionally, stellar masses are inferred from model isochrones to determine the surface gravities. These data show that a new calibration of effective temperatures with errors well under 100K is now possible from interferometric angular diameters of stars.Comment: Accepted for publication in The Astrophysical Journa

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

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    Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
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