47 research outputs found

    Off-road sampling reveals a different grassland bird community than roadside sampling: implications for survey design and estimates to guide conservation

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    Grassland bird species continue to decline steeply across North America. Road-based surveys such as the North American Breeding Bird Survey (BBS) are often used to estimate trends and population sizes and to build species distribution models for grassland birds, although roadside survey counts may introduce bias in estimates because of differences in habitats along roadsides and in off-road surveys. We tested for differences in land cover composition and in the avian community on 21 roadside-based survey routes and in an equal number of adjacent off-road walking routes in the grasslands of southern Alberta, Canada. Off-road routes (n = 225 point counts) had more native grassland and short shrubs and less fallow land and road area than the roadside routes (n = 225 point counts). Consequently, 17 of the 39 bird species differed between the two route types in frequency of occurrence and relative abundance, measured using an indicator species analysis. Six species, including five obligate grassland species, were more prevalent at off-road sites; they included four species listed under the Canadian federal Species At Risk Act or listed by the Committee on the Status of Endangered Wildlife in Canada: Sprague's Pipit (Anthus spragueii), Baird's Sparrow (Ammodramus bairdii), the Chestnut-collared Longspur (Calcarius ornatus), and McCown's Longspur (Rhynchophanes mccownii). The six species were as much as four times more abundant on off-road sites. Species more prevalent along roadside routes included common species and those typical of farmland and other human-modified habitats, e.g., the European Starling (Sturnus vulgaris), the Black-billed Magpie (Pica hudsonia), and the House Sparrow (Passer domesticus). Differences in avian community composition between roadside and off-road surveys suggest that the use of BBS data when generating population estimates or distribution models may overestimate certain common species and underestimate others of conservation concern. Our results highlight the need to develop appropriate corrections for bias in estimates derived from roadside sampling, and the need to design surveys that sample bird communities across a more representative cross-section of the landscape, both near and far from roads

    Recombination between Polioviruses and Co-Circulating Coxsackie A Viruses: Role in the Emergence of Pathogenic Vaccine-Derived Polioviruses

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    Ten outbreaks of poliomyelitis caused by pathogenic circulating vaccine-derived polioviruses (cVDPVs) have recently been reported in different regions of the world. Two of these outbreaks occurred in Madagascar. Most cVDPVs were recombinants of mutated poliovaccine strains and other unidentified enteroviruses of species C. We previously reported that a type 2 cVDPV isolated during an outbreak in Madagascar was co-circulating with coxsackieviruses A17 (CA17) and that sequences in the 3â€Č half of the cVDPV and CA17 genomes were related. The goal of this study was to investigate whether these CA17 isolates can act as recombination partners of poliovirus and subsequently to evaluate the major effects of recombination events on the phenotype of the recombinants. We first cloned the infectious cDNA of a Madagascar CA17 isolate. We then generated recombinant constructs combining the genetic material of this CA17 isolate with that of the type 2 vaccine strain and that of the type 2 cVDPV. Our results showed that poliovirus/CA17 recombinants are viable. The recombinant in which the 3â€Č half of the vaccine strain genome had been replaced by that of the CA17 genome yielded larger plaques and was less temperature sensitive than its parental strains. The virus in which the 3â€Č portion of the cVDPV genome was replaced by the 3â€Č half of the CA17 genome was almost as neurovirulent as the cVDPV in transgenic mice expressing the poliovirus cellular receptor gene. The co-circulation in children and genetic recombination of viruses, differing in their pathogenicity for humans and in certain other biological properties such as receptor usage, can lead to the generation of pathogenic recombinants, thus constituting an interesting model of viral evolution and emergence

    Molecular imaging of rheumatoid arthritis by radiolabelled monoclonal antibodies: new imaging strategies to guide molecular therapies

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    The closing of the last century opened a wide variety of approaches for inflammation imaging and treatment of patients with rheumatoid arthritis (RA). The introduction of biological therapies for the management of RA started a revolution in the therapeutic armamentarium with the development of several novel monoclonal antibodies (mAbs), which can be murine, chimeric, humanised and fully human antibodies. Monoclonal antibodies specifically bind to their target, which could be adhesion molecules, activation markers, antigens or receptors, to interfere with specific inflammation pathways at the molecular level, leading to immune-modulation of the underlying pathogenic process. These new generation of mAbs can also be radiolabelled by using direct or indirect method, with a variety of nuclides, depending upon the specific diagnostic application. For studying rheumatoid arthritis patients, several monoclonal antibodies and their fragments, including anti-TNF-α, anti-CD20, anti-CD3, anti-CD4 and anti-E-selectin antibody, have been radiolabelled mainly with 99mTc or 111In. Scintigraphy with these radiolabelled antibodies may offer an exciting possibility for the study of RA patients and holds two types of information: (1) it allows better staging of the disease and diagnosis of the state of activity by early detection of inflamed joints that might be difficult to assess; (2) it might provide a possibility to perform ‘evidence-based biological therapy’ of arthritis with a view to assessing whether an antibody will localise in an inflamed joint before using the same unlabelled antibody therapeutically. This might prove particularly important for the selection of patients to be treated since biological therapies can be associated with severe side-effects and are considerably expensive. This article reviews the use of radiolabelled mAbs in the study of RA with particular emphasis on the use of different radiolabelled monoclonal antibodies for therapy decision-making and follow-up

    Mouse mesenchymal stem cells inhibit high endothelial cell activation and lymphocyte homing to lymph nodes by releasing TIMP-1.

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    Mesenchymal stem cells (MSC) represent a promising therapeutic approach in many diseases in view of their potent immunomodulatory properties, which are only partially understood. Here, we show that the endothelium is a specific and key target of MSC during immunity and inflammation. In mice, MSC inhibit activation and proliferation of endothelial cells in remote inflamed lymph nodes (LNs), affect elongation and arborization of high endothelial venules (HEVs) and inhibit T-cell homing. The proteomic analysis of the MSC secretome identified the tissue inhibitor of metalloproteinase-1 (TIMP-1) as a potential effector molecule responsible for the anti-angiogenic properties of MSC. Both in vitro and in vivo, TIMP-1 activity is responsible for the anti-angiogenic effects of MSC, and increasing TIMP-1 concentrations delivered by an Adeno Associated Virus (AAV) vector recapitulates the effects of MSC transplantation on draining LNs. Thus, this study discovers a new and highly efficient general mechanism through which MSC tune down immunity and inflammation, identifies TIMP-1 as a novel biomarker of MSC-based therapy and opens the gate to new therapeutic approaches of inflammatory diseases

    Off-road sampling reveals a different grassland bird community than roadside sampling: implications for survey design and estimates to guide conservation

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    ABSTRACT. Grassland bird species continue to decline steeply across North America. Road-based surveys such as the North American Breeding Bird Survey (BBS) are often used to estimate trends and population sizes and to build species distribution models for grassland birds, although roadside survey counts may introduce bias in estimates because of differences in habitats along roadsides and in off-road surveys. We tested for differences in land cover composition and in the avian community on 21 roadside-based survey routes and in an equal number of adjacent off-road walking routes in the grasslands of southern Alberta, Canada. Off-road routes (n = 225 point counts) had more native grassland and short shrubs and less fallow land and road area than the roadside routes (n = 225 point counts). Consequently, 17 of the 39 bird species differed between the two route types in frequency of occurrence and relative abundance, measured using an indicator species analysis. Six species, including five obligate grassland species, were more prevalent at off-road sites; they included four species listed under the Canadian federal Species At Risk Act or listed by the Committee on the Status of Endangered Wildlife in Canada: Sprague's Pipit (Anthus spragueii), Baird's Sparrow (Ammodramus bairdii), the Chestnut-collared Longspur (Calcarius ornatus), and McCown's Longspur (Rhynchophanes mccownii). The six species were as much as four times more abundant on off-road sites. Species more prevalent along roadside routes included common species and those typical of farmland and other human-modified habitats, e.g., the European Starling (Sturnus vulgaris), the Black-billed Magpie (Pica hudsonia), and the House Sparrow (Passer domesticus). Differences in avian community composition between roadside and off-road surveys suggest that the use of BBS data when generating population estimates or distribution models may overestimate certain common species and underestimate others of conservation concern. Our results highlight the need to develop appropriate corrections for bias in estimates derived from roadside sampling, and the need to design surveys that sample bird communities across a more representative cross-section of the landscape, both near and far from roads. L'Ă©chantillonnage hors route rĂ©vĂšle une communautĂ© d'oiseaux de prairie diffĂ©rente de celle issue de l'Ă©chantillonnage le long des routes : rĂ©percussions sur la conception des relevĂ©s et les estimations pour orienter la conservation RÉSUMÉ. Le dĂ©clin prononcĂ© des espĂšces d'oiseaux de prairie se poursuit en AmĂ©rique du Nord. Les relevĂ©s le long des routes, comme le RelevĂ© des oiseaux nicheurs (BBS) en AmĂ©rique du Nord, sont souvent utilisĂ©s pour estimer les tendances et la taille des populations, ainsi que pour Ă©laborer des modĂšles de rĂ©partition d'espĂšces de prairie, mĂȘme si les dĂ©nombrements le long des routes peuvent introduire des biais relatifs aux estimations Ă©tant donnĂ© que les milieux le long des routes sont diffĂ©rents de ceux hors route. Nous avons examinĂ© s'il y avait des diffĂ©rences dans l'occupation du sol et les communautĂ©s aviaires pour 21 routes en bordure desquelles se font des relevĂ©s et pour 21 trajets hors route adjacents dans les prairies du sud de l'Alberta, Canada. Avian Conservation and Ecology 9(1): 4 http://www.ace-eco.org/vol9/iss1/art4/ composition des communautĂ©s aviaires entre les relevĂ©s le long des routes et hors route laissent croire que l'utilisation des donnĂ©es du BBS pour gĂ©nĂ©rer des estimations de population ou des modĂšles de rĂ©partition surestime peut-ĂȘtre certaines espĂšces communes et sousestiment possiblement des espĂšces dont la conservation est prĂ©occupante. Nos rĂ©sultats soulignent le besoin d'Ă©laborer des correctifs appropriĂ©s pour les biais relatifs aux estimations gĂ©nĂ©rĂ©es Ă  partir de l'Ă©chantillonnage le long des routes, et le besoin de concevoir des relevĂ©s qui mesurent les communautĂ©s aviaires dans un Ă©chantillon plus reprĂ©sentatif du paysage, tant prĂšs que loin des routes

    Ship propulsion kites An initial study

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    Available from British Library Lending Division - LD:8258.9254(SSSU--19) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

    Comparison of two kite force models with experiment

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    Kite propulsion has emerged as an attractive means to harness wind power in a way that yields environmental and finanical benefits. This paper compares results from two line tension models with experimentall recorded time histories for dynamic kite flight. New methodologies for investigating kite performance are established. The first zero mass model assumes that the kite and lines are weightless. The second lumped mass model considers the kite's mass and thus makes use of the equations of motion. It is found that the two different models converge to the same result in the limit where the kite mass tends to zero. Kite mass is shown to affect performance only to a relatively small extent. The zero mass model has shown to compare favorably with experimental results for the prediction of performance during three-dimensional kite trajectorie
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