306 research outputs found

    Host community diversity interacts with soil biota and water availability to predict foliar pathogen damage and diversity on tallgrass prairie plants.

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    The provisioning of ecosystem services in tallgrass prairies is mediated by interactions between the plants, their associated above- and belowground microbiota, and the abiotic environment, but global change alters these interactions through a variety of pathways. This study investigates the interactions between belowground microbiota, foliar pathogens, and their host plants in order to better understand how ecosystem functioning may change in a tallgrass prairie system under an altered watering regime. The project focuses on North American tallgrass prairie ecosystems and asks whether host plant diversity and abundance, soil biota, and water availability interactively affect plant susceptibility to damage by a wide range of aboveground pathogens and herbivores in a large outdoor experimental garden. Surveyed plant communities include monocultures of each of seventeen focal plant species and six-species polycultures containing one or more of the focal species. Each community is planted in either the presence or absence of live soil biota, and plant communities are watered to replicate natural soil moisture conditions in a prairie ecosystem or are subjected to drought conditions. Individual plants were assessed for foliar damage by each of eight different groups of foliar pathogens and herbivores, quantified as percent of the leaf surface damaged. Plants grown in monoculture communities experienced more foliar damage from more diverse sources than plants grown in polyculture communities, suggesting that low diversity plant communities accumulate more foliar pathogens than high diversity plant communities, and that plants in low-diversity communities are more susceptible to damage from foliar pathogens than plants in high-diversity communities. Additionally, host plant community diversity, soil community composition, and water availability interacted to influence foliar pathogen damage but not diversity of damage sources. These interactive effects suggest that the identities of the soil biota, host plants, and foliar pathogens influence the host plant’s susceptibility to foliar infection. Ultimately, our ability to manage ecosystems in a sustainable way which maintains the provisioning of valuable ecosystem services is dependent on a nuanced understanding of the underlying interactions which drive these ecosystems. This study attempts to disentangle the interactions between plants and their associated microbiota under a changing climate in order to provide insight to an understudied facet of tallgrass prairie management

    Sexual appeals in social marketing : the influence of feminism and sexual attitude

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    xi, 133 leaves : ill. ; 29 cmThis study examined how females react to the use of sexual appeals in a social marketing context. Sexual appeal was operationalized as the use of female models who are suggestively dressed. Outcome variables, offensiveness, attitude towards the ad and behaviour intention were tested. Feminism and sexual attitude were included as moderators. Three phases were conducted: pretest, short interviews and main study. The pretest and main study used a within study experimental design. Two hundred and nineteen women participated in the main study. It was discovered that overall individuals are offended by the use of suggestiveness, have a lower attitude towards the ad and are less inclined to perform the proposed behaviour. Feminism had no influence on an individual’s reaction while sexual attitude only influenced offensiveness. This study has implications for social marketers who currently use sexual appeals to promote their behaviour as sexual appeals could results in a negative effect

    Using hand proportions to test taxonomic boundaries within the \u3ci\u3eTupaia glis\u3c/i\u3e species complex (Scandentia, Tupaiidae)

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    Treeshrews (order Scandentia) comprise 2 families of squirrel-sized terrestrial, arboreal, and scansorial mammals distributed throughout much of tropical South and Southeast Asia. The last comprehensive taxonomic revision of treeshrews was published in 1913, and a well-supported phylogeny clarifying relationships among all currently recognized extant species within the order has only recently been published. Within the family Tupaiidae, 2 widely distributed species, the northern treeshrew, Tupaia belangeri (Wagner, 1841), and the common treeshrew, T. glis (Diard, 1820), represent a particularly vexing taxonomic complex. These 2 species are currently distinguished primarily based on their respective distributions north and south of the Isthmus of Kra on the Malay Peninsula and on their different mammae counts. This problematic species complex includes 54 published synonyms, many of which represent putative island endemics. The widespread T. glis and T. belangeri collectively comprise a monophyletic assemblage representing the sister lineage to a clade composed of the golden-bellied treeshrew, T. chrysogaster Miller, 1903 (Mentawai Islands), and the long-footed treeshrew, T. longipes (Thomas, 1893) (Borneo). As part of a morphological investigation of the T. glis–T. belangeri complex, we studied the proportions of hand bones, which have previously been shown to be useful in discriminating species of soricids (true shrews). We measured 38 variables from digital X-ray images of 148 museum study skins representing several subspecies of T. glis, T. belangeri, T. chrysogaster, and T. longipes and analyzed these data using principal components and cluster analyses. Manus proportions among these 4 species readily distinguish them, particularly in the cases of T. chrysogaster and T. longipes. We then tested the distinctiveness of several of the populations comprising T. glis and T. longipes. T. longipes longipes and T. l. salatana Lyon, 1913, are distinguishable from each other, and populations of T. ‘‘glis’’ from Bangka Island and Sumatra are distinct from those on the Malay Peninsula, supporting the recognition of T. salatana, T. discolor Lyon, 1906, and T. ferruginea Raffles, 1821 as distinct species in Indonesia. These relatively small, potentially vulnerable treeshrew populations occur in the Sundaland biodiversity hotspot and will require additional study to determine their appropriate conservation status

    Using hand proportions to test taxonomic boundaries within the \u3ci\u3eTupaia glis\u3c/i\u3e species complex (Scandentia, Tupaiidae)

    Get PDF
    Treeshrews (order Scandentia) comprise 2 families of squirrel-sized terrestrial, arboreal, and scansorial mammals distributed throughout much of tropical South and Southeast Asia. The last comprehensive taxonomic revision of treeshrews was published in 1913, and a well-supported phylogeny clarifying relationships among all currently recognized extant species within the order has only recently been published. Within the family Tupaiidae, 2 widely distributed species, the northern treeshrew, Tupaia belangeri (Wagner, 1841), and the common treeshrew, T. glis (Diard, 1820), represent a particularly vexing taxonomic complex. These 2 species are currently distinguished primarily based on their respective distributions north and south of the Isthmus of Kra on the Malay Peninsula and on their different mammae counts. This problematic species complex includes 54 published synonyms, many of which represent putative island endemics. The widespread T. glis and T. belangeri collectively comprise a monophyletic assemblage representing the sister lineage to a clade composed of the golden-bellied treeshrew, T. chrysogaster Miller, 1903 (Mentawai Islands), and the long-footed treeshrew, T. longipes (Thomas, 1893) (Borneo). As part of a morphological investigation of the T. glis–T. belangeri complex, we studied the proportions of hand bones, which have previously been shown to be useful in discriminating species of soricids (true shrews). We measured 38 variables from digital X-ray images of 148 museum study skins representing several subspecies of T. glis, T. belangeri, T. chrysogaster, and T. longipes and analyzed these data using principal components and cluster analyses. Manus proportions among these 4 species readily distinguish them, particularly in the cases of T. chrysogaster and T. longipes. We then tested the distinctiveness of several of the populations comprising T. glis and T. longipes. T. longipes longipes and T. l. salatana Lyon, 1913, are distinguishable from each other, and populations of T. ‘‘glis’’ from Bangka Island and Sumatra are distinct from those on the Malay Peninsula, supporting the recognition of T. salatana, T. discolor Lyon, 1906, and T. ferruginea Raffles, 1821 as distinct species in Indonesia. These relatively small, potentially vulnerable treeshrew populations occur in the Sundaland biodiversity hotspot and will require additional study to determine their appropriate conservation status

    Development of a broadly protective modified-live virus vaccine candidate against porcine reproductive and respiratory syndrome virus

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    Modified-live virus (MLV) vaccines are widely used to protect pigs against porcine reproductive and respiratory syndrome virus (PRRSV). However, current MLV vaccines do not confer adequate levels of heterologous protection, presumably due to the substantial genetic diversity of PRRSV isolates circulating in the field. To overcome this genetic variation challenge, we recently generated a synthetic PRRSV strain containing a consensus genomic sequence of PRRSV-2. We demonstrated that our synthetic PRRSV strain confers unprecedented levels of heterologous protection. However, the synthetic PRRSV strain at passage 1 (hereafter designated CON-P1) is highly virulent and therefore, is not suitable to be used as a vaccine in pigs. In the present study, we attenuated CON-P1 by continuously passaging the virus in MARC-145 cells, a non-natural host cell line. Using a young pig model, we demonstrated that the synthetic virus at passages 90 and 122 (designated as CON-P90 and CON-P122, respectively) were fully attenuated, as evidenced by the significantly reduced viral loads in serum and tissues and the absence of lung lesion in the infected pigs. Most importantly, CON-P90 confers similar levels of heterologous protection as its parental strain CON-P1. Taken together, the results indicate that CON-P90 is an excellent candidate for the formulation of next generation of PRRSV MLV vaccines with improved levels of heterologous protection

    The effects of clam fishing on the properties of surface sediments in the lagoon of Venice, Italy

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    International audienceHarvesting of clams(Tapes philippinarum) has important socio-economic and environmental implications for the Venice lagoon area, Italy. Clam harvesting disrupts the structure of benthic communities but the effects upon sediment stability and surface structure remain unclear. The effect of clam fishing on the sediment properties of the lagoon bed was investigated at two different sites, a heavily fished site (San Angelo) and an infrequently fished site (San Giaccomo). Both sites were assessed for immediate impacts of fishing, using indicators of biogenic sediment stabilisation. Samples were taken at three points along three 100 m linear transects at each site prior to and post fishing. Paired samples were also taken parallel to each transect at a distance of 5m, to allow for temporal variation. Sediment stability, measured with a cohesive strength meter (CSM), was significantly higher at the less impacted site (F1,34 = 6.23, p a (chl a), colloidal-S carbohydrate and dry bulk density were observed on the transect after fishing but not adjacent to the fishing path. At the heavily impacted site, clam fishing by trawling had, in general, no significant effect on the biological and physical properties (although chl a did decrease significantly after fishing). The lack of a significant impact from fishing at the impacted site was attributed to the higher frequency of fishing occurring in this area. Hence, frequent fishing of the lagoon prevents establishment of biotic communities, preventing biostabilisation and thus reduces the stability of the surface sediment. Keywords: clam harvesting, erosion threshold, microphytobenthos, sediment, stabilit

    Host Transcriptional Response to Persistent Infection with a Live-Attenuated Porcine Reproductive and Respiratory Syndrome Virus Strain

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    Both virulent and live-attenuated porcine reproductive and respiratory syndrome virus (PRRSV) strains can establish persistent infection in lymphoid tissues of pigs. To investigate the mechanisms of PRRSV persistence, we performed a transcriptional analysis of inguinal lymphoid tissue collected from pigs experimentally infected with an attenuated PRRSV strain at 46 days post infection. A total of 6404 differentially expressed genes (DEGs) were detected of which 3960 DEGs were upregulated and 2444 DEGs were downregulated. Specifically, genes involved in innate immune responses and chemokines and receptors associated with T-cell homing to lymphoid tissues were down regulated. As a result, homing of virus-specific T-cells to lymphoid tissues seems to be ineffective, evidenced by the lower frequencies of virus-specific T-cell in lymphoid tissue than in peripheral blood. Genes associated with T-cell exhaustion were upregulated. Likewise, genes involved in the anti-apoptotic pathway were upregulated. Collectively, the data suggested that the live-attenuated PRRSV strain establishes a pro-survival microenvironment in lymphoid tissue by suppressing innate immune responses, T-cell homing, and preventing cell apoptosis

    Finite Temperature Time-Dependent Effective Theory for the Phase Field in two-dimensional d-wave Neutral Superconductor

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    We derive finite temperature time-dependent effective actions for the phase of the pairing field, which are appropriate for a 2D electron system with both non-retarded d- and s-wave attraction. As for s-wave pairing the d-wave effective action contains terms with Landau damping, but their structure appears to be different from the s-wave case due to the fact that the Landau damping is determined by the quasiparticle group velocity v_{g}, which for d-wave pairing does not have the same direction as the non-interacting Fermi velocity v_{F}. We show that for d-wave pairing the Landau term has a linear low temperature dependence and in contrast to the s-wave case are important for all finite temperatures. A possible experimental observation of the phase excitations is discussed.Comment: 23 pages, RevTeX4, 10 EPS figures; final version to appear in PR

    Evaluation of Dynamic Models of Distillation Columns with Emphasis on the Initial Response

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    The flow dynamics (tray hydraulics) are of key importance for the initial dynamic response of distillation columns. The most important parameters are the liquid holdup, the liquid hydraulic time constant and the vapor constant representing the initial effect of a change in vapor flow on liquid flow. In the paper we present methods for determining these parameters experimentally, and compare the results with estimates from available correlations such as the Francis Weir formula

    Embodying the Spirit(s): Pentecostal Demonology and Deliverance Discourse in Ethiopia

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    The article explores Pentecostal embodiment practices and concepts with regard to Holy Spirit baptism and demon possession. The studied material is connected to a specific and highly controversial debate in Ethiopian Pentecostalism, which revolves around the possibility of demon possession in born-again and Spirit-filled Christians. This debate runs through much of Ethiopian Pentecostal history and ultimately is concerned with whether or how Christians can host conflicting spiritual forces, in light of the strong dualism between God and evil in Pentecostal cosmology. The article shows that the embodiment of spirits and/or the Holy Spirit is related to theological concepts of the self, because these concepts define what may or may not be discerned in certain bodily manifestations. Moreover, the article contends that this debate thrives on a certain ambiguity in spirit embodiment, which invites the discernment of spiritual experts and thereby becomes a resource of power
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