62 research outputs found

    Comparative Immune Function in Wild Birds

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    Over the last several decades, interest in quantifying immune function in comparative studies of wild animals has grown appreciably. Now, the field of ecological immunology is undergoing a transition, and ¿second generation¿ studies are being designed and carried out. With a greater appreciation of the complexity of immune systems, these second generation studies are commonly distinguished from their antecedents by making comparisons using multiple assays and including multiple species. I worked to advance this transition by developing novel approaches to comparative immunology, exploring the interrelationships among indices of immune function, and applying multiple indices to a question of comparative avian evolution. First, I worked to develop individual methodologies that would be broadly applicable given the numerous limitations of field-based immunology. I present methodological details on two assays¿a hemolysis-hemagglutination assay and a bacteria killing assay, and I report on intra- and inter-specific comparisons using both. Relatedly, using ten species of waterfowl, I examine how these and other indices correlate at both the individual and species levels. Next, with an interest in developing a better understanding of the evolutionary forces molding immune function, I set out to broadly compare immune function in 15 phylogenetically matched pairs of bird populations from North America and from the islands of Hawaii, Bermuda, and the Gal¿pagos. If immune defenses were costly, populations from relatively disease-free, oceanic islands are expected to exhibit attenuated immune function in response to reduced pathogen and parasite pressure. In fact, many island animals exhibit this postulated ¿island syndrome,¿ one facet of which is increased susceptibility to disease. After employing three protocols to measure eight indices of immune function, I found no support for my hypothesis. Rather than evidence of depauperate parasite communities and inherent costs of immune defenses selecting for reduced immune function, I found that several indices were elevated in island birds. I suggest that life on islands is accompanied by an apparent reorganization of the relative importance of various immune components. Finally, in collaborative efforts with investigators here and at other institutions, I apply the hemolysis-hemagglutination assay to address a variety of questions across three diverse avian study systems

    Crop Updates 2001 - Oilseeds

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    ABSTRACT This session covers twenty five papers from different authors: FORWARD, Mervyn McDougall, CHAIRMAN, PULSES AND OILSEEDS PARTNERSHIP GROUP PLENARY 1. Implications of the ‘green-bridge’ for viral and fungal disease carry-over between seasons, Debbie Thackray, Agriculture Western Australia and Centre for Legumes in Mediterranean Agriculture 2. Insect pest development in WA via the ‘green-bridge’, Kevin Walden, Agriculture Western Australia VARIETIES 3. Performance of new canola varieties in AGWEST variety trials, G. Walton, Crop Improvement Institute, Agriculture Western Australia 4. New herbicide tolerant varieties in WA, Kevin Morthorpe, Stephen Addenbrooke, Pioneer Hi-Bred Australia P/L 5. IT v’s TT – Head to head, Paul Carmody, Centre for Cropping Systems, Agriculture Western Australia ESTABLISHMENT 6. Effect of stubble, seeding technique and seed size on crop establishment and yield of canola, Rafiul Alam, Glen Riethmuller and Greg Hamilton, Agriculture Western Australia 7. Canola establishment survey 2000, Rafiul Alam, Paul Carmody, Greg Hamilton and Adrian Cox, Agriculture Western Australia 8. Tramline farming for more canola, Paul Blackwell, Agriculture Western Australia NUTRITION 9. Comparing the phosphorus requirement of canola and wheat in WA, M.D.A. Bolland and M.J. Baker, Agriculture Western Australia 10. Will a rainy summer affect nitrogen requirement: Tailoring your fertiliser decisions using the new nitrogen calculator, A.J. Diggle, Agriculture Western Australia 11. Canola – More response to lime, Chris Gazeyand Paul Carmody, Centre for Cropping Systems, Agriculture Western Australia AGRONOMY 12. Hormone manipulation of canola development, Paul Carmody and Graham Walton, Agriculture Western Australia 13. Yield penalties with delayed sewing of canola, Imma Farre, CSIRO Plant Industry, Michael J. Robertson, CSIRO Sustainable Ecosystems, Graham H. Walton, Agriculture Western Australia, Senthold Asseng, CSIRO Plant Industry 14. Dry matter and oil accumulation in developing seeds of canola varieties at different sowing dates, Ping Si1, David Turner1 and David Harris2 , 1Plant Sciences, Faculty of Agriculture, The University of Western Australia, 2Chemistry Centre of Western Australia 13. Simulating oil concentrations in canola – virtually just the beginning, David Turner1 and Imma Farré2, 1Plant Sciences, Faculty of Agriculture, The University of Western Australia, 2CSIRO Plant Industry, Centre for Mediterranean Agricultural Research PESTS AND DISEASES 14. Further evidence that canola crops are resilient to damage by aphids, Françoise Berlandier and Christiaan Valentine, Entomology, Agriculture Western Australia 15. Management of Diamondback moth (DBM) in canola, David Cook, Peter Mangano, David Cousins, Françoise Berlandier, and Darryl Hardie, Crop Improvement Institute,Agriculture Western Australia 16. Effect of time of sowing in conjunction with fungicides on blackleg and yield of canola, Ravjit Khangura and Martin Barbetti, Agriculture Western Australia 17. Further developments in forecasting aphid and virus risk in canola, Debbie Thackray, Jenny Hawkes and Roger Jones, Agriculture Western Australia and Centre for Legumes in Mediterranean Agriculture 18. Efficiency of selected insecticides for the use on Diamondback Moth in canola, Kevin Walden, Agriculture Western Australia 19. Impact® applied ‘in furrow’ controls blackleg in canola, Cameron Weeks and Erin Hasson, Mingenew-Irwin Group Inc. 20. Effect of time of sowing and Impact® on canola yield, Esperance, Dave Eksteen, Agriculture Western Australia 21. Australian Plague Locust Campaign 2000, Kevin Walden, Agriculture Western Australia WEED CONTROL 22. New herbicide options for canola, John Moore and Paul Matson, Agriculture Western Australia HARVESTING 23. Effects of time of swathing and desiccant application on the seed yield and oil content of canola, Carla Thomas and Lionel Martin, Muresk Institute of Agriculture, Curtin University of Technology DECISION SUPPORT AND ADOPTION 24. Using canola monitoring groups to understand factors affecting canola production in Esperance, Dave Eksteen, Agriculture Western Australia 25. Nitrogen and canola, Dave Eksteen, Agriculture Western Australi

    TOI-332 b: a super dense Neptune found deep within the Neptunian desert

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    To date, thousands of planets have been discovered, but there are regions of the orbital parameter space that are still bare. An example is the short period and intermediate mass/radius space known as the ‘Neptunian desert’, where planets should be easy to find but discoveries remain few. This suggests unusual formation and evolution processes are responsible for the planets residing here. We present the discovery of TOI-332 b, a planet with an ultra-short period of 0.78 d that sits firmly within the desert. It orbits a K0 dwarf with an effective temperature of 5251 ± 71 K. TOI-332 b has a radius of 3.200.12+0.163.20^{+0.16}_{-0.12} R⊕, smaller than that of Neptune, but an unusually large mass of 57.2 ± 1.6 M⊕. It has one of the highest densities of any Neptune-sized planet discovered thus far at 9.61.3+1.19.6^{+1.1}_{-1.3} g cm−3. A 4-layer internal structure model indicates it likely has a negligible hydrogen-helium envelope, something only found for a small handful of planets this massive, and so TOI-332 b presents an interesting challenge to planetary formation theories. We find that photoevaporation cannot account for the mass-loss required to strip this planet of the Jupiter-like envelope it would have been expected to accrete. We need to look towards other scenarios, such as high-eccentricity migration, giant impacts, or gap opening in the protoplanetary disc, to try and explain this unusual discovery

    Crop Updates 2002 - Geraldton

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    This session covers twenty seven papers from different authors: 1. Taking the Why out of Wyalkatchem – the new widely adapted wheat variety, Steve Penny Jr, Department of Agriculture 2. Future wheat varieties, Robin Wilson, Iain Barclay,Robyn McLean, Robert Loughman, Jenny Garlinge, Bill Lambe, Neil Venn and Peter Clarke Department of Agriculture 3. Maximising wheat variety performance through agronomic management, Wal Anderson, Raffaele Del Cima, James Bee, Darshan Sharma, Sheena Lyon, Melaine Kupsch, Mohammad Amjad, Pam Burgess, Veronika Reck, Brenda Shackley, Ray Tugwell, Bindi Webb and Steve Penny Jr Department of Agriculture 4. Cereal rust update 2002 – a new stem rust on Camm wheat, Robert Loughman1and Robert Park2 1Department of Agriculture, 2University of Sydney 5. Influence of nutrition and environmental factors on seed vigour in wheat, Darshan Sharma, Wal Anderson and Daya Patabendige, Department of Agriculture 6. Cereal aphids and direct feeding damage to cereals, Phil Michael, Department of Agriculture 7. A decision support system for control of aphids and BYDV in cereal crops, Debbie Thackray, Jenny Hawkes and Roger Jones, Department of Agriculture and Centre for Legumes in Mediterranean Agriculture 8. Summary of 2001 weather and seasonal prospects for 2002, David Stephens, Department of Agriculture 9. Towards a management package for grain protein in lupins, Bob French, Senior Research Officer, Department of Agriculture 10. Lupin genotypes respond differently to potash, Bob French and Laurie Wahlsten, Senior Research Officer and Technical Officer, Department of Agriculture 11. Time of harvest for improved seed yield of pulses, G. Riethmuller and B. French, Department of Agriculture 12. Comparing the phosphorus requirement of field pea and wheat, M. Bolland and P. White, Department of Agriculture Western Australia 13. Field pea variety evaluation, T. Khan, Department of Agriculture Western Australia 14. Diamondback moth (DBM) in canola, Kevin Walden, Department of Agriculture 15. WA blackleg resistance ratings on canola varieties for 2002, Ravjit Khangura, Martin J. Barbetti and Graham Walton, Department of Agriculture 16. The effect of single or multiple spray treatments on the control of Diamondback moth (Plutella xylostella) and yield of canola at Wongan Hills, Françoise Berlandier, Paul Carmody and Christiaan Valentine, Department of Agriculture 17. Perennial pastures in annual cropping systems: Lucerne and beyond, Roy Latta and Keith Devenish, Department of Agriculture 18. Nutrition in 2002: Decisions to be made as a result of last season, Bill Bowden,Department of Agriculture 19. Profitability of deep banding lime, Michael O\u27Connell, Chris Gazey and David Gartner, Department of Agriculture 20. Economic comparisons of farming systems for the medium rainfall northern sandplain, Caroline Peek and David Rogers, Department of Agriculture 21. The use of Twist Fungus as a biosecurity measure against Annual Ryegrass Toxicity (ARGT), Greg Shea, GrainGuard Coordinator and George Yan, Biological and Resource Technology 22. Major outcomes from IWM demonstration sites, Alexandra Douglas, Department of Agriculture 23. Understanding the weed seed bank life of important agricultural weeds, Sally Peltzer and Paul Matson, Department of Agriculture 24. Seeding rate, row spacing and herbicides for weed control, David Minkey, Department of Agriculture 25. Improving weed control in grazed pastures using legumes with low palatability, Clinton Revell and Giles Glasson, Department of Agriculture, Dean Thomas, Faculty of Agriculture, University of Western Australia 26. Group F resistant wild radish: What’s new? Aik Cheam1, Siew Lee1and Mike Clarke2, 1Department of Agriculture WA, 2Aventis Crop Science 27. Knockdown herbicides do not reliably kill small grass weeds, Peter Newman and Glenn Adam, Department of Agricultur

    A pair of TESS planets spanning the radius valley around the nearby mid-M dwarf LTT 3780

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    We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, V=13.07V=13.07, Ks=8.204K_s=8.204, RsR_s=0.374 R_{\odot}, MsM_s=0.401 M_{\odot}, d=22 pc). The two planet candidates are identified in a single TESS sector and are validated with reconnaissance spectroscopy, ground-based photometric follow-up, and high-resolution imaging. With measured orbital periods of Pb=0.77P_b=0.77 days, Pc=12.25P_c=12.25 days and sizes rp,b=1.33±0.07r_{p,b}=1.33\pm 0.07 R_{\oplus}, rp,c=2.30±0.16r_{p,c}=2.30\pm 0.16 R_{\oplus}, the two planets span the radius valley in period-radius space around low mass stars thus making the system a laboratory to test competing theories of the emergence of the radius valley in that stellar mass regime. By combining 63 precise radial-velocity measurements from HARPS and HARPS-N, we measure planet masses of mp,b=2.620.46+0.48m_{p,b}=2.62^{+0.48}_{-0.46} M_{\oplus} and mp,c=8.61.3+1.6m_{p,c}=8.6^{+1.6}_{-1.3} M_{\oplus}, which indicates that LTT 3780b has a bulk composition consistent with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope. We show that the recovered planetary masses are consistent with predictions from both photoevaporation and from core-powered mass loss models. The brightness and small size of LTT 3780, along with the measured planetary parameters, render LTT 3780b and c as accessible targets for atmospheric characterization of planets within the same planetary system and spanning the radius valley.Comment: Accepted to AJ. 8 figures, 6 tables. CSV file of the RV measurements (i.e. Table 2) are included in the source cod

    Affectus Hispaniae en la historiografía del Alto Imperio

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    This paper analyses texts written by Greek and Latin High Empire historians dealing with Hispania. Some of the authors have a very positive view (Florus, Iustinus, Appian) while others are clearly negative (Veleius Paterculus, Valerius Maximus) though most of them show little interest, indifference or variety of opinions. When there is interest in the region or praise, it is because the author comes from Hispania or he is trying to please an emperor born in Hispania, but it could also be due to a universal conception of history revealing a critical attitude towards Roman imperialism, as in Appian. The praise found in Iustinus’s epitome should be attributed to the author of the epitome rather than to Pompeius Trogus. This can be taken as evidence for situating Iustinus’s life and work in the 2nd century A.D. Loathing of Hispania seems to have its origins in conservative, ‘optimate’ nationalist circles, who perceive the province as the ‘popular’ region that acclaimed and welcomed ‘seditious’ individuals such as Tiberius Gracchus and Sertorius.Se estudian en este trabajo los textos de historiadores del Alto Imperio, latinos y griegos, que tratan sobre Hispania. En algunos autores encontramos una visión muy positiva (Floro, Justino, Apiano) y en otros claramente negativa (Veleyo Patérculo, Valerio Máximo), aunque en la mayoría de los casos hay escasa atención, indiferencia o diversidad de opiniones. El interés por la región y los elogios pueden estar motivados por el origen hispánico del autor o su voluntad de agradar a algún emperador oriundo de Hispania, pero también por una concepción universal de la historia que denota en ocasiones una posición crítica con el imperialismo romano, como es el caso de Apiano. La alabanza que hallamos en el epítome de Justino creemos que debe atribuirse más al epitomador que a Pompeyo Trogo, lo que apoyaría una datación temprana de la vida y la obra de Justino (s. II d.C.). La aversión hacia Hispania parece haber surgido en medios conservadores, “optimates” nacionalistas, que ven la provincia como el territorio “popular”, que encumbró y acogió a “sediciosos” como Tiberio Graco y Sertorio

    The TESS-Keck Survey II: An Ultra-Short Period Rocky Planet and its Siblings Transiting the Galactic Thick-Disk Star TOI-561

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    We report the discovery of TOI-561, a multi-planet system in the galactic thick disk that contains a rocky, ultra-short period planet (USP). This bright (V=10.2V=10.2) star hosts three small transiting planets identified in photometry from the NASA TESS mission: TOI-561 b (TOI-561.02, P=0.44 days, Rb=1.45±0.11RR_b = 1.45\pm0.11\,R_\oplus), c (TOI-561.01, P=10.8 days, Rc=2.90±0.13RR_c=2.90\pm0.13\,R_\oplus), and d (TOI-561.03, P=16.3 days, Rd=2.32±0.16RR_d=2.32\pm0.16\,R_\oplus). The star is chemically ([Fe/H]=0.41±0.05=-0.41\pm0.05, [α\alpha/H]=+0.23±0.05=+0.23\pm0.05) and kinematically consistent with the galactic thick disk population, making TOI-561 one of the oldest (10±310\pm3\,Gyr) and most metal-poor planetary systems discovered yet. We dynamically confirm planets b and c with radial velocities from the W. M. Keck Observatory High Resolution Echelle Spectrometer. Planet b has a mass and density of 3.2±0.8M3.2\pm0.8\,M_\oplus and 5.51.6+2.05.5^{+2.0}_{-1.6}\,g\,cm3^{-3}, consistent with a rocky composition. Its lower-than-average density is consistent with an iron-poor composition, although an Earth-like iron-to-silicates ratio is not ruled out. Planet c is 7.0±2.3M7.0\pm2.3\,M_\oplus and 1.6±0.61.6\pm0.6\,g\,cm3^{-3}, consistent with an interior rocky core overlaid with a low-mass volatile envelope. Several attributes of the photometry for planet d (which we did not detect dynamically) complicate the analysis, but we vet the planet with high-contrast imaging, ground-based photometric follow-up and radial velocities. TOI-561 b is the first rocky world around a galactic thick-disk star confirmed with radial velocities and one of the best rocky planets for thermal emission studies.Comment: Accepted at The Astronomical Journal; 25 pages, 10 figure

    The L 98-59 System: Three Transiting, Terrestrial-size Planets Orbiting a Nearby M Dwarf

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    We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia-measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the corresponding stellar parameters yield planet radii ranging from 0.8 R ⊕ to 1.6 R ⊕. All three planets have short orbital periods, ranging from 2.25 to 7.45 days with the outer pair just wide of a 2:1 period resonance. Diagnostic tests produced by the TESS Data Validation Report and the vetting package DAVE rule out common false-positive sources. These analyses, along with dedicated follow-up and the multiplicity of the system, lend confidence that the observed signals are caused by planets transiting L 98-59 and are not associated with other sources in the field. The L 98-59 system is interesting for a number of reasons: the host star is bright (V = 11.7 mag, K = 7.1 mag) and the planets are prime targets for further follow-up observations including precision radial-velocity mass measurements and future transit spectroscopy with the James Webb Space Telescope; the near-resonant configuration makes the system a laboratory to study planetary system dynamical evolution; and three planets of relatively similar size in the same system present an opportunity to study terrestrial planets where other variables (age, metallicity, etc.) can be held constant. L 98-59 will be observed in four more TESS sectors, which will provide a wealth of information on the three currently known planets and have the potential to reveal additional planets in the system
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