71 research outputs found

    The Science Case for a Return to Enceladus

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    The plume of Enceladus is unique in the solar system in providing direct access to fresh material from an extraterrestrial subsurface ocean. The Cassini Mission, though not specifically designed for it, was able to take advantage of the plume to conduct the best characterization to date of an extraterrestrial ocean. Evidence gathered from multiple instruments points to a global, subsurface liquid water ocean rich in salts and organic compounds, with water-rock interactions occurring presumably in hydrothermal systems at or below the moon’s sea floor. Meeting the criteria of “extended regions of liquid water, conditions favorable for the assembly of complex organic molecules, and energy source(s) to sustain metabolism,” the ocean of Enceladus can therefore be considered habitable. It is also the only confirmed place beyond the Earth where we can easily sample fresh material from a demonstrably habitable environment without the complications of digging or drilling. The next step is to investigate whether Enceladus’ ocean is actually inhabited. Here, we summarize the evidence for Enceladus’ ocean and its habitability, identify constraints and outstanding questions on the detectability of life within its ocean, and recommend a return to Enceladus with a dedicated search-for-life mission (or missions)

    Evaluating complementary and alternative medicine interventions: in search of appropriate patient-centered outcome measures

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    BACKGROUND: Central to the development of a sound evidence base for Complementary and Alternative Medicine (CAM) interventions is the need for valid, reliable and relevant outcome measures to assess whether the interventions work. We assessed the specific needs for a database that would cover a wide range of outcomes measures for CAM research and considered a framework for such a database. METHODS: The study was a survey of CAM researchers, practitioners and students. An online questionnaire was emailed to the members of the Canadian Interdisciplinary Network for CAM Research (IN-CAM) and the CAM Education and Research Network of Alberta (CAMera). The majority of survey questions were open-ended and asked about outcome measures currently used, outcome measures' assessment criteria, sources of information, perceived barriers to finding outcome measures and outcome domains of importance. Descriptive quantitative analysis and qualitative content analysis were used. RESULTS: One hundred and sixty-four completed surveys were received. Of these, 62 respondents reported using outcome measures in their CAM research and identified 92 different specific outcomes. The most important barriers were the fact that, for many health concepts, outcome measures do not yet exist, as well as issues related to accessibility of instruments. Important outcome domains identified included physical, psychological, social, spiritual, quality of life and holistic measures. Participants also mentioned the importance of individualized measures that assess unique patient-centered outcomes for each research participant, and measures to assess the context of healing and the process of healing. CONCLUSION: We have developed a preliminary framework that includes all components of health-related outcomes. The framework provides a foundation for a larger, comprehensive collection of CAM outcomes. It fits very well in a whole systems perspective, which requires an expanded set of outcome measures, such as individualized and holistic measures, with attention to issues of process and context

    Proteoglycan Breakdown of Meniscal Explants Following Dynamic Compression Using a Novel Bioreactor

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    Motivated by our interest in examining meniscal mechanotransduction processes, we report on the validation of a new tissue engineering bioreactor. This paper describes the design and performance capabilities of a tissue engineering bioreactor for cyclic compression of meniscal explants. We showed that the system maintains a tissue culture environment equivalent to that provided by conventional incubators and that its strain output was uniform and reproducible. The system incorporates a linear actuator and load cell aligned together in a frame that is contained within an incubator and allows for large loads and small displacements. A plunger with six Teflon-filled Delrin compression rods is attached to the actuator compressing up to six tissue explants simultaneously and with even pressure. The bioreactor system was used to study proteoglycan (PG) breakdown in porcine meniscal explants following various input loading tests (0–20% strain, 0–0.1 MPa). The greatest PG breakdown was measured following 20% compressive strain. These strain and stress levels have been shown to correspond to partial meniscectomy. Thus, these data suggest that removing 30–60% of meniscal tissue will result in the breakdown of meniscal tissue proteoglycans

    Identification and Characterisation of Pseudomonas 16S Ribosomal DNA from Ileal Biopsies of Children with Crohn's Disease

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    Molecular analysis of bacterial 16S rRNA genes has made a significant contribution to the identification and characterisation of bacterial flora in the human gut. In particular, this methodology has helped characterise bacterial families implicated in the aetiology of inflammatory bowel disease (IBD). In this study we have used a genus specific bacterial 16S PCR to investigate the prevalence and diversity of Pseudomonas species derived from the ileum of children with Crohn's disease (CD), and from control children with non-inflammatory bowel disease (non-IBD) undergoing their initial endoscopic examination. Fifty eight percent of CD patients (18/32) were positive using the Pseudomonas PCR, while significantly fewer children in the non-IBD group, 33% (12/36), were PCR positive for Pseudomonas (p<0.05, Fischer's exact test). Pseudomonas specific 16S PCR products from 13 CD and 12 non-IBD children were cloned and sequenced. Five hundred and eighty one sequences were generated and used for the comparative analysis of Pseudomonas diversity between CD and non-IBD patients. Pseudomonas species were less diverse in CD patients compared with non-IBD patients. In particular P.aeruginosa was only identified in non-IBD patients

    Neptune Odyssey: A Flagship Concept for the Exploration of the Neptune–Triton System

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    The Neptune Odyssey mission concept is a Flagship-class orbiter and atmospheric probe to the Neptune-Triton system. This bold mission of exploration would orbit an ice-giant planet to study the planet, its rings, small satellites, space environment, and the planet-sized moon Triton. Triton is a captured dwarf planet from the Kuiper Belt, twin of Pluto, and likely ocean world. Odyssey addresses Neptune system-level science, with equal priorities placed on Neptune, its rings, moons, space environment, and Triton. Between Uranus and Neptune, the latter is unique in providing simultaneous access to both an ice giant and a Kuiper Belt dwarf planet. The spacecraft - in a class equivalent to the NASA/ESA/ASI Cassini spacecraft - would launch by 2031 on a Space Launch System or equivalent launch vehicle and utilize a Jupiter gravity assist for a 12 yr cruise to Neptune and a 4 yr prime orbital mission; alternatively a launch after 2031 would have a 16 yr direct-to-Neptune cruise phase. Our solution provides annual launch opportunities and allows for an easy upgrade to the shorter (12 yr) cruise. Odyssey would orbit Neptune retrograde (prograde with respect to Triton), using the moon's gravity to shape the orbital tour and allow coverage of Triton, Neptune, and the space environment. The atmospheric entry probe would descend in ~37 minutes to the 10 bar pressure level in Neptune's atmosphere just before Odyssey's orbit-insertion engine burn. Odyssey's mission would end by conducting a Cassini-like "Grand Finale,"passing inside the rings and ultimately taking a final great plunge into Neptune's atmosphere

    The Self-Selection of Democracies into Treaty Design: Insights from International Environmental Agreements

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    Generally, democratic regime type is positively associated with participating in international environmental agreements. In this context, this study focuses on the legal nature of an agreement, which is linked to audience costs primarily at the domestic level that occur in case of non-compliance and are felt especially by democracies. Eventually, more legalized (\hard-law") treaties make compliance potentially more challenging and democratic leaders may anticipate the corresponding audience costs, which decreases the likelihood that democracies select themselves into such treaties. The empirical implication of our theory follows that environmental agreements with a larger share of democratic members are less likely to be characterized by hard law. This claim is tested using quantitative data on global environmental treaties. The results strongly support our argument, shed new light on the relationship between participation in international agreements and the form of government, and also have implications for the \words-deeds" debate in international environmental policy-making

    Genome Sequence of the Acute Urethral Catheter Isolate Pseudomonas aeruginosa MH38

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    Wibberg D, Tielen P, Blom J, et al. Genome Sequence of the Acute Urethral Catheter Isolate Pseudomonas aeruginosa MH38. Genome announcements. 2014;2(2): e00161-14.Pseudomonas aeruginosa is a major nosocomial bacterial pathogen causing complicated catheter-associated urinary tract infections (CAUTIs). Here, we present the 6.9-Mb draft genome sequence of P. aeruginosa MH38 isolated from an acute nosocomial CAUTI. It exhibits resistance to several antibiotics but revealed low-level production of virulence factors

    Enceladus Life Finder: the Search for Life in a Habitable Moon

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    Enceladus is one of the most intriguing bodies in the solar system. In addition to having one of the brightest and youngest surfaces, this small Saturnian moon was recently discovered to have a plume erupting from its south polar terrain and a global subsurface ocean. The Cassini Mission discovered organics and nitrogen-bearing molecules in the plume, as well as salts and silicates that strongly suggest ocean water in contact with a rocky core. However, Cassini's instruments lack sufficient resolution and mass range to determine if these organics are of biotic origin. The Enceladus Life Finder (ELF) is a Discovery-class mission that would use two state-of-the-art mass spectrometers to target the gas and grains of the plume and search for evidence of life in this alien ocean
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