739 research outputs found

    UCDs as Probes of the Major and Minor Merger Histories of Galaxies

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    Two competing theories posit that Ultra Compact Dwarfs (UCDs) form either as the stripped nuclei of dwarf galaxies or as giant globular clusters (GGCs) associated with the largest globular cluster (GC) systems. By focussing on the field and group environments where young UCDs may be most common, we have discovered the first UCD that is clearly the result of recent (<4 Gyr ago) stripping of a companion galaxy. However, we have also found a definitive case of a multiple-UCD system created via GC formation processes, which are likely associated with major galaxy mergers. We demonstrate that it is possible to reliably distinguish the two types of UCD, thereby probing both the major and minor merger histories of individual galaxies.Comment: 2 pages, 1 figure, to appear in the proceedings of the conference "A Universe of Dwarf Galaxies" (Lyon, June 14-18, 2010

    Duration of antibody response following vaccination against feline immunodeficiency virus

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    Objectives: Recently, two point-of-care (PoC) feline immunodeficiency virus (FIV) antibody test kits (Witness and Anigen Rapid) were reported as being able to differentiate FIV-vaccinated from FIV-infected cats at a single time point, irrespective of the gap between testing and last vaccination (0–7 years). The aim of the current study was to investigate systematically anti-FIV antibody production over time in response to the recommended primary FIV vaccination series. Methods: First, residual plasma from the original study was tested using a laboratory-based ELISA to determine whether negative results with PoC testing were due to reduced as opposed to absent antibodies to gp40. Second, a prospective study was performed using immunologically naive client-owned kittens and cats given a primary FIV vaccination series using a commercially available inactivated whole cell/inactivated whole virus vaccine (Fel-O-Vax FIV, three subcutaneous injections at 4 week intervals) and tested systematically (up to 11 times) over 6 months, using four commercially available PoC FIV antibody kits (SNAP FIV/FeLV Combo [detects antibodies to p15/p24], Witness FeLV/FIV [gp40], Anigen Rapid FIV/FeLV [p24/gp40] and VetScan FeLV/FIV Rapid [p24]). Results: The laboratory-based ELISA showed cats from the original study vaccinated within the previous 0–15 months had detectable levels of antibodies to gp40, despite testing negative with two kits that use gp40 as a capture antigen (Witness and Anigen Rapid kits). The prospective study showed that antibody testing with SNAP Combo and VetScan Rapid was positive in all cats 2 weeks after the second primary FIV vaccination, and remained positive for the duration of the study (12/12 and 10/12 cats positive, respectively). Antibody testing with Witness and Anigen Rapid was also positive in a high proportion of cats 2 weeks after the second primary FIV vaccination (8/12 and 7/12, respectively), but antibody levels declined below the level of detection in most cats (10/12) by 1 month after the third (final) primary FIV vaccination. All cats tested negative using Witness and Anigen Rapid 6 months after the third primary FIV vaccination. Conclusions and relevance: This study has shown that a primary course of FIV vaccination does not interfere with FIV antibody testing in cats using Witness and Anigen Rapid, provided primary vaccination has not occurred within the previous 6 months. Consequently, Witness and Anigen Rapid antibody test kits can be used reliably to determine FIV infection status at the time of annual booster FIV vaccination to help detect ‘vaccine breakthroughs’ and in cats that have not received a primary course of FIV vaccination within the preceding 6 months. The duration of antibody response following annual booster FIV vaccination and the resulting effect on antibody testing using PoC kits needs to be determined by further research. The mechanism(s) for the variation in FIV antibody test kit performance remains unclear

    Creative Self-Efficacy, Technology Acceptance, and the Theory of Planned Behavior: Antecedents to a Maker's Intention to Return to Make

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    Fab Labs, Makerspaces and Hackerspaces are part of a decentralized global Do-It-Yourself movement providing unique resources to tinkerers, hobbyists, inventors and artists to make almost anything. Individuals who use these facilities are often called “makers.” This preliminary research offers insight into why people intend to return to making by testing a proposed Maker Behavioral Model based on the Theory of Planned Behavior, the technology acceptance model, and creative self-efficacy. This model proposes three key characteristics which predict an individual’s intentions to continue making, namely social interactions, creative behaviors, and perceived behavioral control. A survey of the membership of Fab Lab Tulsa and other U.S.-based Fab Labs was used to test the maker model by examining the members’ attitudes and behaviors about creativity and making, technology, their social group, their openness to experience, and their creative role identity. It also examined the correlation with their intention to return to make. The results demonstrate that perceived behavioral control is the biggest predictor of maker intention, followed by creative behaviors and social interactions. Technology perceptions were related to social interactions but did not predict intention. This preliminary research has implications for any Fab Lab that seeks to bolster its membership, improve its staffing or increase facility usage. Future work should include development of the survey for non-English speakers and non U.S. cultures

    Understanding the Effects of Cross-Linking Density on the Self-Healing Performance of Epoxidized Natural Rubber and Natural Rubber

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    [Image: see text] The demand for self-healing elastomers is increasing due to the potential opportunities such materials offer in reducing down-time and cost through extended product lifetimes and reduction of waste. However, further understanding of self-healing mechanisms and processes is required in order to develop a wider range of commercially applicable materials with self-healing properties. Epoxidized natural rubber (ENR) is a derivative of polyisoprene. ENR25 and ENR50 are commercially available materials with 25 and 50 mol % epoxidation, respectively. Recently, reports of the use of ENR in self-healing materials have begun to emerge. However, to date, there has been limited analysis of the self-healing mechanism at the molecular level. The aim of this work is to gain understanding of the relevant self-healing mechanisms through systematic characterization and analysis of the effect of cross-linking on the self-healing performance of ENR and natural rubber (NR). In our study, cross-linking of ENR and NR with dicumyl peroxide and sulfur to provide realistic models of commercial rubber formulations is described, and a cross-linking density of 5 × 10(–5) mol cm(–3) in sulfur-cured ENR is demonstrated to achieve a healing efficiency of 143% for the tensile strength. This work provides the foundation for further modification of ENR, with the goal of understanding and controlling ENR’s self-healing ability for future applications

    The measurement of approximate number system acuity across the lifespan is compromised by congruency effects

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    Recent studies have highlighted the influence of visual cues such as dot size and cumulative surface area on the measurement of the approximate number system (ANS). Previous studies assessing ANS acuity in ageing have all applied stimuli generated by the Panamath protocol, which does not control nor measure the influence of convex hull. Crucially, convex hull has recently been identified as an influential visual cue present in dot arrays, with its impact on older adults’ ANS acuity yet to be investigated. The current study therefore investigated the manipulation of convex hull by the Panamath protocol, and its effect on the measurement of ANS acuity in younger and older participants. Firstly, analyses of the stimuli generated by Panamath revealed a confound between numerosity ratio and convex hull ratio. Secondly, although older adults were somewhat less accurate than younger adults on convex hull incongruent trials, ANS acuity was broadly similar between the groups. These findings have implications for the valid measurement of ANS acuity across all ages, and suggest that the Panamath protocol produces stimuli that do not adequately control for the influence of convex hull on numerosity discrimination

    A systematic review of the psychosocial adjustment of children and adolescents with facial palsy: The impact of Moebius syndrome

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    Introduction: Facial palsy is often associated with impaired facial function and altered appearance. However, the literature with regards to the psychological adjustment of children and adolescents with facial palsy has not been systematically reviewed to date. This paper aimed to review all published research with regards to psychosocial adjustment for children and adolescents with facial palsy. Methods: MEDLINE, CINAHL, Embase, PsychInfo and AMED databases were searched and data was extracted with regards to participant characteristics, study methodology, outcome measures used, psychosocial adjustment and study quality. Results: Five studies were eligible for inclusion, all of which investigated psychosocial adjustment in participants with Moebius syndrome, a form of congenital facial palsy. Many parents reported their children to have greater social difficulties than general population norms, with difficulties potentially increasing with age. Other areas of psychosocial adjustment, including behaviour, anxiety and depression, were found to be more comparable to the general population. Discussion: Children and adolescents with Moebius syndrome may experience social difficulties. However, they also demonstrate areas of resilience. Further research including individuals with facial palsy of other aetiologies is required in order to determine the psychosocial adjustment of children and adolescents with facial palsy

    Common and Antarctic Minke Whales: Conservation Status and Future Research Directions

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    Minke whales comprise some of the most widely distributed species of baleen whales, some populations of which are still regularly targeted by commercial whaling. Here, we review the conservation status of common (Balaenoptera acutorostrata) and Antarctic (Balaenoptera bonaerensis) minke whale populations, against the backdrop of ongoing whaling operations and other anthropogenic threats, including climate change, entanglement in fishing gear, ship strikes, and noise pollution. Although some coastal minke whale populations have been studied in detail, others, which inhabit remote and ecologically sensitive locations, such as the Antarctic ice shelf, are among the least understood populations of marine mammals. The unresolved taxonomy of dwarf minke whales further highlights some of the existing knowledge gaps concerning these species. Due to their relatively small size and elusive behaviors, large uncertainties exist for almost all minke whale populations with respect to behavior, migratory routes and winter distributions, hindering effective conservation and management. However, recent advances in research technology, such as passive acoustic monitoring (PAM), unmanned aerial systems (UAS), multisensor recording tags, and machine learning assisted photo-identification, are increasingly being applied to study minke whales and their habitat, and are starting to open new windows into their life history and ecology. In future research, these non- and less-invasive methods should be integrated in larger-scale comparative studies aiming to better understand minke whale behavior, ecological interactions and their varying habitats to drive and support effective species conservation
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