58 research outputs found

    A super-Earth and a sub-Neptune orbiting the bright, quiet M3 dwarf TOI-1266

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    We report the discovery and characterisation of a super-Earth and a sub-Neptune transiting the bright (K=8.8K=8.8), quiet, and nearby (37 pc) M3V dwarf TOI-1266. We validate the planetary nature of TOI-1266 b and c using four sectors of TESS photometry and data from the newly-commissioned 1-m SAINT-EX telescope located in San Pedro M\'artir (Mexico). We also include additional ground-based follow-up photometry as well as high-resolution spectroscopy and high-angular imaging observations. The inner, larger planet has a radius of R=2.370.12+0.16R=2.37_{-0.12}^{+0.16} R_{\oplus} and an orbital period of 10.9 days. The outer, smaller planet has a radius of R=1.560.13+0.15R=1.56_{-0.13}^{+0.15} R_{\oplus} on an 18.8-day orbit. The data are found to be consistent with circular, co-planar and stable orbits that are weakly influenced by the 2:1 mean motion resonance. Our TTV analysis of the combined dataset enables model-independent constraints on the masses and eccentricities of the planets. We find planetary masses of MpM_\mathrm{p} = 13.59.0+11.013.5_{-9.0}^{+11.0} M\mathrm{M_{\oplus}} (<36.8<36.8 M\mathrm{M_{\oplus}} at 2-σ\sigma) for TOI-1266 b and 2.21.5+2.02.2_{-1.5}^{+2.0} M\mathrm{M_{\oplus}} (<5.7<5.7 M\mathrm{M_{\oplus}} at 2-σ\sigma) for TOI-1266 c. We find small but non-zero orbital eccentricities of 0.090.05+0.060.09_{-0.05}^{+0.06} (<0.21<0.21 at 2-σ\sigma) for TOI-1266 b and 0.04±0.030.04\pm0.03 (<0.10<0.10 at 2-σ\sigma) for TOI-1266 c. The equilibrium temperatures of both planets are of 413±20413\pm20 K and 344±16344\pm16 K, respectively, assuming a null Bond albedo and uniform heat redistribution from the day-side to the night-side hemisphere. The host brightness and negligible activity combined with the planetary system architecture and favourable planet-to-star radii ratios makes TOI-1266 an exquisite system for a detailed characterisation

    Temporal Analysis of Feeding Patterns of Culex erraticus in Central Alabama

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    Host blood meals in seven mosquito species previously shown to be infected with eastern equine encephalitis virus at a site in the Tuskegee National Forest in southcentral Alabama were investigated. Of 1374 blood meals derived from 88 different host species collected over 6 years from these seven mosquito species, 1099 were derived from Culex erraticus. Analysis of the temporal pattern of Cx. erraticus meals using a Runs test revealed that the patterns of feeding upon avian and mammalian hosts from March to September of each year were not randomly distributed over time. Similarly, meals taken from the three most commonly targeted host species (yellow-crowned night heron, great blue heron, and white-tailed deer) were not randomly distributed. A Tukey's two-way analysis of variance test demonstrated that although the temporal pattern of meals taken from avian hosts were consistent over the years, the patterns of meals taken from the individual host species were not consistent from year to year

    Bottlenecks in the Open-Access System: Voices from Around the Globe

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    <p>A level playing field is key for global participation in science and scholarship, particularly with regard to how scientific publications are financed and subsequently accessed. However, there are potential pitfalls of the so-called “Gold” open-access (OA) route, in which author-paid publication charges cover the costs of production and publication. <br>Gold OA plans in which author charges are required may not solve the access problem, but rather may shift the access barrier from reader to writer. Under such plans, everyone may be free to read papers, but it may still be prohibitively expensive to publish them. In a scholarly community that is increasingly global, spread over more and more regions and countries of the world, these publication access barriers may be quite significant. <br>In the present paper, a global suite of colleagues in academe joins this debate. The group of colleagues, a network of researchers active in scholarly publishing, spans four continents and multiple disciplines in the natural sciences, humanities, and social sciences, as well as diverse political and economic situations. We believe that this global <br>sampling of researchers can provide the nuance and perspective necessary to grasp this complex problem. The group was assembled without an attempt to achieve global coverage through random sampling. <br>This contribution differs from other approaches to the open-access problem in several fundamental ways. (A) It is scholar-driven, and thus can represent the ‘other side of the coin’ of scholarly communication. (B) It focuses on narrative report, where scholars were free to orient their responses as they saw fit, rather than being confined to binary or scalar choices. Finally, and perhaps most importantly, (C) it distinguishes among institutions and countries and <br>situations, highlighting inequalities of access among wealthy and economically-challenged nations, and also within countries depending on the size and location of particular institutions.</p

    Climatic niche divergence drives patterns of diversification and richness among mammal families

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    A major goal of evolutionary biology is to understand why clades difer dramatically in species richness. A key to this challenge is to uncover the correlates of variation in diversifcation rate (speciation – extinction) among clades. Here, we explore the relationship between diversifcation rates and the climatic niches of species and clades among 92 families of terrestrial mammals. We use a time-calibrated molecular phylogeny of mammals and climatic data from 3335 species. We show that considerable variation in net diversifcation rates among mammal families is explained by niche divergence (59%) and rates of niche change (51%). Diversifcation rates in turn explain most variation in species richness among families (79%). Contrary to expectations, patterns of diversifcation are not explained by diferences in geographic range areas of clades, nor by their climatic niche position (i.e. whether they are primarily tropical or temperate). Overall, these results suggest that speciation through climatic niche divergence may help drive large-scale patterns of diversifcation and richness. Our results help explain diversifcation patterns in a major clade of vertebrates, and suggest that similar underlying principles may explain the diversifcation of many terrestrial cladesThis work was supported by the Spanish Ministry of Economy and Competitiveness and ERDF funds (grants CGL2013-43350-P and CGL2016-76637-P, and fellowship IJCI-2014-20881 to C.G.R.) and Xunta de Galicia (PhD fellowship ED481A-2015/074 to A.C.I and postdoctoral fellowship POS-A/2012/052 to C.G.R.)S
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