241 research outputs found

    Body Composition, Parasite Loads, and Blood Parameters of Spring-migrating Lesser Scaup in the Upper Midwest

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    The abundance and relative composition of helminth communities in the lower gut of LESC differed among regions. Total helminths and % trematodes increased and % cestodes decreased with increasing latitude. Measures of scaup health differed by region, and generally decreased with increasing latitude. Perturbations in health parameters that can be associated with infectious disease or other health insult (e.g., PCV, increased lymphocytes, reduced heterophil/lymphocyte ratios, reduced monocytes) reflected the geographic pattern of infection with the highly pathogenic trematode Sphaeridiotrema pseudoglobulus. However, some exceptions were apparent and may reflect the combined effects of healthy and infected birds. For example, CMRV included LESC from Mississippi River pool 19, considered high quality habitat, and pool 12, where ducks were infected with S. pseudoglobulus. Patterns of variation in measures of condition were less clear. For example, fresh mass of LESC increased with latitude, with the exception of ducks from UMRV in 2014. This was reflected in lower carcass lipids, triglycerides and NEFA and increased BHB in that sample. Ducks collected from IRV were in poorer condition in 2015 than 2014, judging by a decline in carcass lipids without a concomitant decrease in mass. These results suggest interactions between annual wetland conditions (i.e., food availability) and infectious disease agents (highly-pathogenic intestinal helminths). In the sequel, we intend to further explore these patterns and interrelationships with the addition of the outstanding 2015 LESC health data, helminth community analyses, and incorporation of wetland quality indices.IDNR Division of Wildlife RC09-13FWUIUCunpublishednot peer reviewe

    The forgotten '45 : Donald Dubh's rebellion in an archipelagic context

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    The final rebellion of Donald Dubh, heir to the forfeited MacDonald lordship of the Isles, is usually examined within the context of Highland rebellions that occurred in the half century after forfeiture. However, the factors that motivated the Islesmen to rise in rebellion in 1545 are multi-faceted and can only be fully understood by placing the rising in a wider context, which considers national and archipelagic events. The discussion that follows explores the reasons why the Islesmen, almost unanimously, entered into agreement with Henry VIII to attack Scotland from the west and why this endeavour failed. At the same time, the article highlights Henry’s recognition of the strategic importance of the west which led him into alliance with Donald Dubh and his supporters

    Elements Discrimination in the Study of Super-Heavy Elements using an Ionization Chamber

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    Dedicated ionization chamber was built and installed to measure the energy loss of very heavy nuclei at 2.7 MeV/u produced in fusion reactions in inverse kinematics (beam of 208Pb). After going through the ionization chamber, products of reactions on 12C, 18O targets are implanted in a Si detector. Their identification through their alpha decay chain is ambiguous when their half-life is short. After calibration with Pb and Th nuclei, the ionization chamber signal allowed us to resolve these ambiguities. In the search for rare super-heavy nuclei produced in fusion reactions in inverse or symmetric kinematics, such a chamber will provide direct information on the nuclear charge of each implanted nucleus.Comment: submitted to NIMA, 10 pages+4 figures, Latex, uses elsart.cls and grahpic

    The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

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    This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics

    The tree that hides the forest: Cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus Complex (Diptera: Ceratopogonidae) at the European level

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    Background: Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex. Methods: Portion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex. Results: Our analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus. Conclusions: To our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region.[Figure not available: See fulltext.

    Back to the future : using long-term observational and paleo-proxy reconstructions to improve model projections of Antarctic climate

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    Quantitative estimates of future Antarctic climate change are derived from numerical global climate models. Evaluation of the reliability of climate model projections involves many lines of evidence on past performance combined with knowledge of the processes that need to be represented. Routine model evaluation is mainly based on the modern observational period, which started with the establishment of a network of Antarctic weather stations in 1957/58. This period is too short to evaluate many fundamental aspects of the Antarctic and Southern Ocean climate system, such as decadal-to-century time-scale climate variability and trends. To help address this gap, we present a new evaluation of potential ways in which long-term observational and paleo-proxy reconstructions may be used, with a particular focus on improving projections. A wide range of data sources and time periods is included, ranging from ship observations of the early 20th century to ice core records spanning hundreds to hundreds of thousands of years to sediment records dating back 34 million years. We conclude that paleo-proxy records and long-term observational datasets are an underused resource in terms of strategies for improving Antarctic climate projections for the 21st century and beyond. We identify priorities and suggest next steps to addressing this
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