647 research outputs found

    Preliminary Canopy Removal Experiments in Algal Dominated Communities Low on the Shore and in the Shallow Subtidal on the Isle of Man

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    The algal dominated communities immediately above and below the low-water spring level on a moderately exposed Manx shore were investigated by canopy removal experiments. Fucus serratus, Laminaria digitata and L. hyperborea were removed. Competition was shown to be important in determining the zonation of L. digitata and the distribution along the wave exposure gradient of other species such as Alaria esculenta, Desmarestia aculeata and D. viridis, and L. saccharina. Many species of algal epiphytes were early colonizers of canopy removal areas suggesting that competition from canopy algae usually restricts them to an epiphytic habit. The results indicate that interactions between macrophytes are much more important than grazing in structuring these communities

    Navigating cancer using online communities: a grounded theory of survivor and family experiences

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    Purpose: People affected by cancer often have unmet emotional and social support needs. Online cancer communities are a convenient channel for connecting cancer survivors, allowing them to support one another. However, it is unclear whether online community use makes a meaningful contribution to cancer survivorship, as little previous research has examined the experience of using contemporary cancer communities. We aimed to explore the experiences of visitors to online cancer communities. Methods: Twenty-three in-depth interviews were conducted with online cancer community visitors, including cancer survivors (n = 18), family members (n = 2), and individuals who were both a survivor and family member (n = 3). Interviews were analysed using a grounded theory approach. Results: A theory developed explaining how individuals ‘navigated’ the experience of cancer using online cancer communities. Online advice and information led participants on a ‘journey to become informed’. Online friendships normalised survivorship and cast participants on a ‘journey to recreate identity’. Participants navigated a ‘journey through different worlds’ as they discovered relevant and hidden communities. Conclusions: This theory highlights virtual paths people affected by cancer can take to self-manage their experience of the disease. Online community experiences can be improved by promoting online evaluation skills and signposting visitors to bereavement support. Implications for cancer survivors: Cancer survivors can benefit through both lurking and posting in online communities. However, individuals risk becoming distressed when they befriend individuals who may soon die. Additionally, people affected by rarer cancers can struggle to find shared experiences online and may need to look elsewhere for support

    Fault-tolerant networks-on-chip routing with coarse and fine-grained look-ahead

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    Fault tolerance and adaptive capabilities are challenges for modern networks-on-chip (NoC) due to the increase in physical defects in advanced manufacturing processes. Two novel adaptive routing algorithms, namely coarse and fine-grained (FG) look-ahead algorithms, are proposed in this paper to enhance 2-D mesh/torus NoC system fault-tolerant capabilities. These strategies use fault flag codes from neighboring nodes to obtain the status or conditions of real-time traffic in an NoC region, then calculate the path weights and choose the route to forward packets. This approach enables the router to minimize congestion for the adjacent connected channels and also to bypass a path with faulty channels by looking ahead at distant neighboring router paths. The novelty of the proposed routing algorithms is the weighted path selection strategies, which make near-optimal routing decisions to maintain the NoC system performance under high fault rates. Results show that the proposed routing algorithms can achieve performance improvement compared to other state of the art works under various traffic loads and high fault rates. The routing algorithm with FG look-ahead capability achieves a higher throughput compared with the coarse-grained approach under complex fault patterns. The hardware area/power overheads of both routing approaches are relatively low which does not prohibit scalability for large-scale NoC implementations

    On the horns of a dilemma: clarity and ambivalence in oppositional writing in the wake of the uprising of 17 June 1953 in the German Democratic Republic

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    A civil Uprising on 17 June 1953 in the German Democratic Republic created a dilemma for a number of writers there. On one hand, they were deeply committed to the principles of socialism, upon which their state was based and which they saw as being put in grave danger by events such as those they experienced on 17 June. On the other hand, they were fiercely critical of the practice of socialism as pursued by the governing party, whose Stalinist methods of governance they believed to be in large part responsible for the civil unrest. My thesis explores the nature of this dilemma in the case of four writers, Bertolt Brecht, Heiner Müller, Stefan Heym and Erich Loest, and their efforts to resolve it within a repressive state, whose regime vigorously suppressed all signs of criticism or dissent. These writers created major works of fiction, a cycle of poems, a drama and two novels, in which the Uprising of 17 June is the central theme. In addition, each has provided a substantial body of non-fictional texts, largely journalistic and autobiographical, in which the Uprising is extensively contextualised. In bringing together and interrelating the fictional and non-fictional work of each author into my analysis, I have been able to demonstrate that all four held and publicly expressed views that set them in opposition to the regime in the GDR

    Modelling and control of a water jet cutting probe for flexible surgical robot

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    Surgical removal of cancerous tissue from the spine is limited by the inability of hand held drills and cutting tools to reach small crevices present in complex bones such as the spinal column, especially on the anterior side. In addition, the high speed rotating mechanisms used presently are subject to stability issues when manoeuvring around tortuous bone forms. We report on the design and experimental testing of a novel flexible robotic surgical system which addresses these issues. The robot consists of a flexible probe, a water jet cutting system, and a haptic feedback controller. The water jet cutting system consists of a flexible end effector capable of bending around the anterior of the spinal column for tissue removal. A new experimental method of controlling the depth of water jet cut is described. The haptic feedback controller is based on a constraint set approach to define 3D boundaries, based on five key types of constraints. Experimental outcomes of measuring the depth of water jet cut were combined with haptic regional constraints with the aim of improving the safety of surgical procedures. The reliability, accuracy and performance of the prototype robot were tested in a mock surgical procedure on the lower lumbar vertebrae. Results show promise for the implementation of water jet cutting for robotic surgical spinal procedures

    In-service Initial Teacher Education in the Learning and Skills Sector in England: Integrating Course and Workplace Learning

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    The aim of the paper is to advance understanding of in-service learning and skills sector trainee teachers’ learning and propose ways of improving their learning. A conceptual framework is developed by extending Billett’s (International Journal of Educational Research 47:232–240, 2008) conceptualisation of workplace learning, as a relationally interdependent process between the opportunities workplaces afford for activities and interactions and how individuals engage with these, to a third base of participation, the affordances of the initial teacher education course. Hager and Hodkinson’s (British Educational Research Journal 35:619–638, 2009) metaphor of ‘learning as becoming’ is used to conceptualise the ways trainees reconstruct learning in a continuous transactional process of boundary crossing between course and workplace. The findings of six longitudinal case studies of trainees’ development, and evidence from other studies, illustrate the complex interrelationships between LSS workplace affordances, course affordances and trainee characteristics and the ways in which trainees reconstruct learning in each setting. The experience of teaching and interacting with learners, interactions with colleagues, and access to workplace resources and training are important workplace affordances for learning. However, some trainees have limited access to these affordances. Teaching observations, course activities and experiences as a learner are significant course affordances. Trainees’ beliefs, prior experiences and dispositions vary and significantly influence their engagement with course and workplace affordances. It is proposed that better integration of course and workplace learning through guided participation in an intentional workplace curriculum and attention to the ways trainees choose to engage with this, together with the use of practical theorising has the potential to improve trainee learning

    Use of PCR to identify Leptospira in kidneys of big brown bats (Eptesicus fuscus) in Kansas and Nebraska, USA

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    Bats have been implicated as potential carriers of Leptospira as a result of surveys, mostly in Australia and South America. We measured the prevalence of pathogenic leptospires in kidneys of bats from Kansas and Nebraska. From 7 August 2012 to 21 August 2012, we extracted DNA from kidneys of 98 big brown bats (Eptesicus fuscus) submitted and found negative for rabies. The DNA was processed in a two-step, seminested PCR assay with a dual-labeled Taqman probe specific for pathogenic leptospires. As a negative control, we used a saprophytic leptospire (Leptospira biflexa Patoc) and, as a pathogenic control, Leptospira interrogans Canicola. All bat kidneys were negative for pathogenic leptospires, suggesting that it is unlikely that the big brown bat, one of the most prevalent bat species in North America, is a reservoir for transmission of leptospires to dogs or humans

    Endovascular repair or open repair for ruptured abdominal aortic aneurysm: a Cochrane systematic review

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    OBJECTIVES: Emergency endovascular aneurysm repair (eEVAR) may improve outcomes for patients with ruptured abdominal aortic aneurysm (RAAA). The study aim was to compare the outcomes for eEVAR with conventional open surgical repair for the treatment of RAAA. SETTING: A systematic review of relevant publications was performed. Randomised controlled trials (RCTs) comparing eEVAR with open surgical repair for RAAA were included. PARTICIPANTS: 3 RCTs were included, with a total of 761 patients with RAAA. INTERVENTIONS: Meta-analysis was performed with fixed-effects models with ORs and 95% CIs for dichotomous data and mean differences with 95% CIs for continuous data. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome was short-term mortality. Secondary outcome measures included aneurysm-specific and general complication rates, quality of life and economic analysis. RESULTS: Overall risk of bias was low. There was no difference between the 2 interventions on 30-day (or in-hospital) mortality, OR 0.91 (95% CI 0.67 to 1.22; p=0.52). 30-day complications included myocardial infarction, stroke, composite cardiac complications, renal complications, severe bowel ischaemia, spinal cord ischaemia, reoperation, amputation and respiratory failure. Reporting was incomplete, and no robust conclusion was drawn. For complication outcomes that did include at least 2 studies in the meta-analysis, there was no clear evidence to support a difference between eEVAR and open repair. Longer term outcomes and cost per patient were evaluated in only a single study, thus precluding definite conclusions. CONCLUSIONS: Outcomes between eEVAR and open repair, specifically 30-day mortality, are similar. However, further high-quality trials are required, as the paucity of data currently limits the conclusions
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