1,127 research outputs found

    Natal Philopatry in Song Sparrows (Melospiza melodia) Predicts Female Cellular Versus Humoral Immune Function, But Does Not Consistently Predict Parasitism

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    Parasites vary geographically and dispersing host individuals may encounter different strains and wider varieties than their philopatric counterparts. Previously observed lower parasite counts in philopatric than dispersing birds have been suggested to be the result of local adaptation to parasites, but I suggest an alternative: these patterns may result from differing immune function. I used genetic assignment tests to infer natal philopatry of song sparrows (Melospiza melodia), and tested whether this predicted parasitism and innate and adaptive immune function. I found no relationship between parasitism and philopatry, in contrast to previous findings. In females, philopatry was associated with higher cellular innate immunity and lower humoral innate immunity. I also detected a negative relationship between measures of cellular adaptive immunity and humoral innate immunity. These results suggest a sex-specific, philopatry-mediated immune tradeoff that occurs along the cellular-humoral axis, rather than the innate-adaptive axis traditionally focused on in ecophysiological life history

    An Evaluation of the Aesthetics of Junkyard Screening and Billboard Densities

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    Mapping cumulative noise from shipping to inform marine spatial planning

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    Including ocean noise in marine spatial planning requires predictions of noise levels on large spatiotemporal scales. Based on a simple sound transmission model and ship track data (Automatic Identification System, AIS), cumulative underwater acoustic energy from shipping was mapped throughout 2008 in the west Canadian Exclusive Economic Zone, showing high noise levels in critical habitats for endangered resident killer whales, exceeding limits of “good conservation status” under the EU Marine Strategy Framework Directive. Error analysis proved that rough calculations of noise occurrence and propagation can form a basis for management processes, because spending resources on unnecessary detail is wasteful and delays remedial action

    Two new pulsating hot subdwarf stars from the Edinburgh-Cape survey

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    We report the discovery of very rapid pulsations in two hot subdwarf stars from the Edinburgh- Cape blue object survey. The short periods, small amplitudes and multiperiodicity establish these stars as members of the class of rapidly-pulsating sdB stars. The spectrograms of both stars, however, show relatively strong He II 4686 and they are therefore more properly classified as sdOB. The light curve of EC 01541?1409 is dominated by two strong (?1 per cent) variations with frequencies near 7114 and 7870 ?Hz (periods near 140.6 and 127.1 s), though at least five frequencies are present with amplitudes above about 0.002 mag. The light curve of EC 22221?3152 appears to be generated by at least 10 frequencies in the range 5670-11850 ?Hz (about 175-85 s) with amplitudes between about 0.01 and 0.001 mag, including the first overtone of the strongest variation. Somewhat surprisingly, this number of frequencies is detectable in observing runs as short as 3 h, probably due to the fact that the detected frequencies are well-separated.IS

    Adverse effects of routine bovine health treatments containing triclabendazole and synthetic pyrethroids on the abundance of dipteran larvae in bovine faeces

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    Macrocyclic lactone treatments for livestock can have detrimental effects on the arthropod populations in livestock faeces. For the last twenty years, avoidance of these products has been a standard recommendation on livestock farms that are managed for wildlife by the Royal Society for Protection of Birds (RSPB). However, the continued decline in the populations of birds (in particular the red-billed chough Pyrrhocorax pyrrhocorax) that are dependent on dung invertebrates on islands in the Inner Hebrides of Scotland prompted us to investigate the effects of livestock treatments that are commonly used on these islands. We conducted a replicated field plot study over two years to quantify the effects of livestock treatments containing copper, deltamethrin and triclabendazole on invertebrate density in pooled, artificial faecal pats on the island of Islay. We found that the density of arthropod larvae was significantly reduced by the triclabendazole and deltamethrin treatments in both years and by as much as 86% when the treatments were combined. Copper-containing boluses did not consistently affect abundance of arthropod larvae. These results suggest that veterinary treatment of livestock might contribute to a reduction in the food supply of chough

    The ESO Key-Programme ``A Homogeneous Bright QSO Survey'' - I The Methods and the ``Deep'' Fields

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    This is the first paper in a series aimed at defining a statistically significant sample of QSOs in the range 15<B<18.75 15 < B < 18.75 and 0.3<z<2.2 0.3 < z < 2.2. The selection is carried out using direct plates obtained at the ESO and UK Schmidt Telescopes, scanned with the COSMOS facility and searched for objects with an ultraviolet excess. Follow-up spectroscopy, carried out at ESO La Silla, is used to classify each candidate. In this initial paper, we describe the scientific objectives of the survey; the selection and observing techniques used. We present the first sample of 285 QSOs (MB<23M_B < -23) in a 153 deg2^2 area, covered by the six ``deep'' fields, intended to obtain significant statistics down B18.75B \simeq 18.75 with unprecedented photometric accuracy. From this database, QSO counts are determined in the magnitude range 17<B<18.75 17 < B < 18.75.Comment: 21 pages uuencoded compressed postscript, to appear in Astronomy and Astrophysics Supplements, 199

    Thrombin A-Chain: Activation Remnant or Allosteric Effector?

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    Although prothrombin is one of the most widely studied enzymes in biology, the role of the thrombin A-chain has been neglected in comparison to the other domains. This paper summarizes the current data on the prothrombin catalytic domain A-chain region and the subsequent thrombin A-chain. Attention is given to biochemical characterization of naturally occurring prothrombin A-chain mutations and alanine scanning mutants in this region. While originally considered to be simply an activation remnant with little physiologic function, the thrombin A-chain is now thought to play a role as an allosteric effector in enzymatic reactions and may also be a structural scaffold to stabilize the protease domain

    Diversifying molecular and topological space via a supramolecular solid-state synthesis: a purely organic mok net sustained by hydrogen bonds

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    A three-dimensional hydrogen-bonded network based on a rare mok topology has been constructed using an organic molecule synthesized in the solid state. The molecule is obtained using a supramolecular protecting-group strategy that is applied to a solid-state [2+2] photodimerization. The photodimerization affords a novel head-to-head cyclobutane product. The cyclobutane possesses tetrahedrally disposed cis-hydrogen-bond donor (phenolic) and cis-hydrogen- bond acceptor (pyridyl) groups. The product self-assembles in the solid state to form a mok network that exhibits twofold interpenetration. The cyclobutane adopts different conformations to provide combinations of hydrogen-bond donor and acceptor sites to conform to the structural requirements of the mok net

    The Firefighter Problem: A Structural Analysis

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    We consider the complexity of the firefighter problem where b>=1 firefighters are available at each time step. This problem is proved NP-complete even on trees of degree at most three and budget one (Finbow et al.,2007) and on trees of bounded degree b+3 for any fixed budget b>=2 (Bazgan et al.,2012). In this paper, we provide further insight into the complexity landscape of the problem by showing that the pathwidth and the maximum degree of the input graph govern its complexity. More precisely, we first prove that the problem is NP-complete even on trees of pathwidth at most three for any fixed budget b>=1. We then show that the problem turns out to be fixed parameter-tractable with respect to the combined parameter "pathwidth" and "maximum degree" of the input graph
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