931 research outputs found

    Differences in behavioural traits among native and introduced colonies of an invasive ant

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    Identifying the factors that promote the success of biological invasions is a key pursuit in ecology. To date, the link between animal personality and invasiveness has rarely been studied. Here, we examined in the laboratory how Argentine ant populations from the species' native and introduced ranges differed in a suite of behaviours related to species interactions and the use of space. We found correlations among specific behavioural traits that defined an explorative-aggressive syndrome. The Main "European" supercolony (introduced range) more readily explored novel environments, displayed more aggression, detected food resources more quickly, and occupied more space than the Catalonian supercolony (introduced range) and two other Argentine supercolonies (native range). The two native supercolonies also differed in their personalities; one harbouring the less invasive personality, while the other is intermediate between the two introduced supercolonies. Therefore, instead of a binary pattern, Argentine ant supercolonies display a behavioural continuum that is independent on their geographic origin (native/introduced ranges). Our results also suggest that variability in personality traits is correlated to differences in the ecological success of Argentine ant colonies. Differences in group personalities may facilitate the persistence and invasion of animals under novel selective pressures by promoting adaptive behaviours. We stress that the concept of animal personality should be taken into account when elucidating the mechanisms of invasiveness

    Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices

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    The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included

    Characterization of Murine Thymic Stromal-Cell Lines Immortalized by Temperature-Sensitive Simian Virus 40 Large T or Adenovirus 5 E1a

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    The heterogeneity of thymic stromal cells is probably related to their role in providing different microenvironments where T cells can develop. We have immortalized thymic stromal elements using recombinant retroviral constructs containing a temperature-sensitive simian virus 40 (SV40tsA58) large-T antigen gene or the adenovirus 5 E1a region linked to the gene coding for resistance to G418. Cell lines containing the thermolabile large T antigen encoded by SV40 proliferate at the permissive temperature of 33°C and arrest growth when transferred to the nonpermissive temperature of 39°C. At the nonpermissive temperature, ts-derived cell lines are shown to alter their phenotype but remain metabolically active, as indicated by the inducible expression of class I and class II MHC antigens. Here we describe the generation of a total of 84 thymic stromal-cell lines, many of which show distinct morphologic, phenotypic, and functional properties consistent with fibroblastoid, epithelial, or monocytoid origins. Several E1a and SV40tsA58-derived cell lines generated exhibit the epithelial characteristic of desmosome formation and, in addition, two of these lines (15.5 and 15.18) form multicellular complexes (rosettes) when incubated with unfractionated thymocytes from syngeneic mice. A single line (14.5) displays very strong nonspecific esterase activity, suggesting it may represent a macrophagelike cell type. We describe the generation of stromal cell lines with different properties, which is consistent with the heterogeneity found in the thymic microenvironment. In addition to documenting this diversity, these cell lines may be useful tools for studying T-cell development in vitro and give access to model systems in which stromal-thymocyte interactions can be examined

    Epidermal Mosaicism and Blaschko\u27s Lines

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    To test the hypothesis that epidermal rather than dermal mosaicism determines Blaschko\u27s lines in hypomelanosis of Ito (HI), we studied the distribution of chromosomal mosaicism in four patients. In two, mosaicism had not been detected in lymphocytes or dermal fibroblasts, but was clearly shown in epidermal keratinocytes; furthermore, the abnormal cell line was confirmed to the hypopigmented epidermis and the normal epidermis contained only normal cells. Negative findings in the other two patients might be because of mosaicism which was undetected either because it was submicroscopic or because it was present in melanocytes, which have not yet been studied. These preliminary results support the ideas that (1) Blaschko\u27s lines represent single clones of epidermal cells; (2) in patients with HI and severe neurological involvement mosaicism, if detectable, is best shown in keratinocytes; and (3) the cytogenetic defect in epidermal cells may be directly responsible for the failure of pigmentation in HI

    Evaluation of a commercially available ELISA kit for detection of antibodies to Anaplasma marginale and Anaplasma centrale in cattle in Australia and Zimbabwe

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    A newly available competitive inhibition ELISA kit for the serological diagnosis of anaplasmosis was evaluated in Australia and Zimbabwe. In Australia the performance of the test was compared with the card agglutination test (CAT). The assay was evaluated using negative sera collected from Anaplasma-free herds, positive sera from experimentally infected cattle and sera from Anaplasma marginale-endemic herds. The sensitivity and specificity of the ELISA in Australia were 100 and 83.3%, respectively, and the sensitivity and specificity of the CAT were both 100%. The agreement between the ELISA and CAT in the sera from endemic herds was 86.4% (kappa=0.718). The specificity of the ELISA in Zimbabwe was 100%. No meaningful estimate of sensitivity was possible in Zimbabwe because few known positive sera were available for testing, but all eight known positive sera that were available were clearly positive. We conclude that the ELISA is a useful alternative to the CAT for epidemiological studies. The ELISA kits have advantages over the CAT in that the ELISA is more robust and reagents are better standardized, but the kits are expensive.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Australian Centre for International Agricultural Research (ACIAR).mn201

    Framework for Integration of Data from Remotely Operated Cameras into Recreational Fishery Assessments in Western Australia

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    Remotely operated cameras can be used for cost-efficient monitoring of recreational fishing activities. This report provides an overview of the current usage of cameras in recreational fishery assessments by the Department of Primary Industries and Regional Development. Since 2006, 32 remotely operated cameras have been installed at 26 locations throughout Western Australia and currently 28 cameras are in use

    Colony-colony interactions between highly invasive ants

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    Among invasive species, ants are a particularly prominent group with enormous impacts on native biodiversity and ecosystem functioning. Globalization and on-going climate change are likely to increase the rate of ant invasions in the future, leading to simultaneous introductions of several highly invasive species within the same area, Here, we investigate pairwise interactions among four highly invasive species, Linepithema humile,Lashis neglectus, Pheidole megacephala and Wasmannia auropunctata, at the whole colony level, using a laboratory set-up. :Each colony consisted of 300 workers and one queen. The number of surviving workers in the competing colonies was recorded daily over 7 weeks. We modelled the survival of each colony during pairwise colony interactions, using a nonlinear model characterizing the survival dynamics of each colony individually. The least dominant species was P. megacephala, which always went extinct. Interactions among the three other species showed more complex dynamics, rendering the outcome of the interactions less predictable. Overall, W auropunctata and L neglectus were the most dominant species. This study shows the importance of scaling up to the colony level in order to gain realism in predicting the outcome of multiple invasions

    Identification of a novel phosphorylation site in hepatitis C virus NS5A

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    Hepatitis C virus (HCV) NS5A protein is phosphorylated on multiple residues; however, despite extensive study, the precise identity of these sites has not been determined unambiguously. In this study, we have used a combination of immunoprecipitation and mass spectrometry to identify these phosphorylation sites. This analysis revealed the presence of a major phosphorylated residue within NS5A from the genotype 1b Con1 isolate – serine 249 (serine 2221 in polyprotein numbering). However, mutation of this residue (or the corresponding threonine in the JFH-1 isolate) to either a phosphomimetic (aspartate) or a phosphoablative (alanine) residue resulted in no phenotype. We conclude that phosphorylation of this residue, in the context of a highly culture-adapted HCV genome, does not play a role in either viral RNA replication or virus assembly. It is possible that it might be important in an aspect of virus biology that is not recapitulated faithfully in the Huh-7 cell-culture system
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