113 research outputs found

    Non-isotopic splitting spheres for a split link in S4S^4

    Full text link
    We show that there exist split, orientable, 2-component surface-links in S4S^4 with non-isotopic splitting spheres in their complements. In particular, for non-negative integers m,nm,n with m4m\ge 4, the unlink Lm,nL_{m,n} consisting of one component of genus mm and one component of genus nn contains in its complement two smooth splitting spheres that are not topologically isotopic in S4Lm,nS^4\setminus L_{m,n}. This contrasts with link theory in the classical dimension, as any two splitting spheres in the complement of a 2-component split link LS3L\subset S^3 are isotopic in S3LS^3\setminus L.Comment: 14 pages with 7 figures. Comments welcome

    Branched covers of twist-roll spun knots

    Full text link
    We prove that the double branched cover of a twist-roll spun knot in S4S^4 is smoothly preserved when four twists are added, and that the double branched cover of a twist-roll spun knot connected sum with a trivial projective plane is preserved after two twists are added. As a consequence, we conclude that a family of homotopy CP2\mathbb{CP}^2s recently constructed by Miyazawa are each diffeomorphic to CP2\mathbb{CP}^2.Comment: Corollary 1.6 had an error and was removed. The authors thank David Baraglia for pointing this error out. 8 pages, 4 figures, comments welcome

    Digital Civic Sensemaking: Computer-Supported Participatory Sensemaking of Nuanced, Experience-Based Dialogue

    Get PDF
    Throughout the 21st century, we have seen a steady decline in trust in democracy, and a proliferation of exclusive, deconstructive methods of political participation such as town halls and polarizing social media discourse. However, methods of facilitated small group dialogue and community organizing have fostered trust, understanding, and civic empowerment for generations. Further, with advances in human-computer interaction, machine learning, and computer-supported cooperation in civic technology, the intersection between dialogue, community organizing, and technology for positive and inclusive civic participation is ripe for exploration. We present Real Talk, a hybrid civic technology program in which we aim to design, develop, and implement scalable technological infrastructure and equip communities, organizations, and networks with the processes and technology that allows them to connect, share experiences, collaborate, make meaning, address problems, suggest and advocate decisions in a thriving ecosystem. In this paper, we discuss a foundational system within the program as a key contribution to system sciences: computer-supported participatory sensemaking of nuanced dialogue data. We outline our system and discuss findings, implications, and shortcomings

    Pathogenic potential of respirable spodumene cleavage fragments following application of regulatory counting criteria for asbestiform fibres

    Get PDF
    Health risks from exposure to lithium-bearing spodumene cleavage fragments are unknown. While asbestiform fibres can lead to fibrosis, mesothelioma and lung cancer, controversy remains whether non-asbestiform cleavage fragments, having equivalent dimensions, elicit similar pathologic responses. The mineralogy of respirable particles from two alpha (α) - spodumene concentrate grades (chemical and technical) were characterised using semi-quantitative X-ray diffraction (XRD). Particles were measured using scanning electron microscopy (SEM) and the dimensions (length [L], diameter [D], aspect ratio [AR]) applied to regulatory counting criteria for asbestiform fibres. Application of the current World Health Organization (WHO) and National Occupational Health and Safety Commission (NOHSC) counting criteria, L ˃ 5 µm, D ˂ 3 µm, AR ˃ 3 : 1, to 10 SEM images of each grade identified 47 countable particles in the chemical and 37 in the technical concentrate test samples. Of these particles, 17 and 16 in the chemical and technical test samples, respectively, satisfied the more rigorous, previously used Mines Safety and Inspection Regulations 1995 (Western Australia [WA]) criteria, L ˃ 5 µm and D ≤ 1 µm. The majority of the countable particles were consistent with α - spodumene cleavage fragments. These results suggest elongated α - spodumene particles may pose a health risk. It is recommended the precautionary principle be applied to respirable α - spodumene particles and the identification and control of dust hazards in spodumene extraction, handling and processing industries be implemented

    The status of Habitats Directive Annex I saltmarsh habitats, transition zones and spartina species in England

    Get PDF
    On unmodified soft sediment coastlines, of which there are long lengths especially on the English east and south coasts, there should be a wide transitional zone between tidal areas and full terrestrial land. The conditions in this zone result in a rich and distinctive range of habitats. There are two saltmarsh habitats listed in Annex I of the Habitats Directive within this zone (H1420 Mediterranean and thermo-Atlantic halophilous scrubs and H1320 Spartina swards,Spartinion maritimae) reflecting its importance for nature conservation. At the time work for this project was started in 2012, the conservation status of these habitats was reported as ‘unfavourable, bad and deteriorating’. Due to construction of artificial sea defences, these zones are now much reduced in extent and distribution and are under threat from a range of factors. This project aims to provide an inventory and description of Annex I saltmarsh habitats and transitional vegetation in England. This will help to update future reporting on conservation status. The outcomes will also help improve understanding of the underpinning processes which can be used in design to improve the potential for recreating these elements of saltmarshes as part of intertidal restoration schemes. The project also provides an up to date assessment of Spartina alterniflora stands in the Solent SAC through review and field survey for 2012

    “Who does this patient belong to?” Boundary work and the re/making of (NSTEMI) heart attack patients

    Get PDF
    This ethnography within ten English and Welsh hospitals explores the significance of boundary work and the impacts of this work on the quality of care experienced by heart attack patients who have suspected non–ST segment elevation myocardial infarction (NSTEMI) /non-ST elevation acute coronary syndrome. Beginning with the initial identification and prioritisation of patients, boundary work informed negotiations over responsibility for patients, their transfer and admission to different wards, and their access to specific domains in order to receive diagnostic tests and treatment. In order to navigate boundaries successfully and for their clinical needs to be more easily recognised by staff, a patient needed to become a stable boundary object. Ongoing uncertainty in fixing their clinical classification, was a key reason why many NSTEMI patients faltered as boundary objects. Viewing NSTEMI patients as boundary objects helps to articulate the critical and ongoing process of classification and categorisation in the creation and maintenance of boundary objects. We show the essential, but hidden, role of boundary actors in making and re-making patients into boundary objects. Physical location was critical and the parallel processes of exclusion and restriction of boundary object status can lead to marginalisation of some patients and inequalities of care.NIHR Research for Patient Benefi

    Understanding variation in patient care: A qualitative study of hospital (non-ST elevation myocardial infarction) practices [version 1; peer review: awaiting peer review].

    Get PDF
    Background Variation in care is often poorly understood but has a big impact on patients. Non-ST segment elevation myocardial infarction (NSTEMI, also known as non-ST elevation acute coronary syndrome or NSTE-ACS) is the most common form of heart attack. NSTEMI is frequently hard to diagnose, its management pathway poorly defined and there is considerable variation in clinical practice. Methods A qualitative study based on site visits, observation, and interviews with managers, clinicians and patients. The setting was 10 hospitals in England and Wales selected to represent variation in 30-day mortality. 199 hospital staff and 68 patients were observed; 142 staff and 53 patients were interviewed. Analysis was thematic and guided by the principles of grounded theory. We triangulated interviews, observational data and medical records and interpreted these findings with reference to national guidelines. Results While the majority of hospitals in our sample had specialist cardiac roles, variation in their remits, specifically their involvement in close monitoring, significantly affected patient management. Close monitoring was important in the identification and prioritisation of patients. Rapid responses with diagnostic and treatment procedures were facilitated by close monitoring but also heavily dependent on effective and flexible bed and catheter laboratory management. Conclusions Close monitoring was a key area of variation. Guidelines for NSTEMI care specify what to do, but not how to do it. These findings are especially relevant for acute conditions with diagnostic and treatment uncertainty. Detailed examples of variation in care can inform quality improvement and potentially help improve patient outcomes

    Aerobiology over Antarctica – a new initiative for atmospheric ecology

    Get PDF
    The role of aerial dispersal in shaping patterns of biodiversity remains poorly understood, mainly due to a lack of coordinated efforts in gathering data at appropriate temporal and spatial scales. It has been long known that the rate of dispersal to an ecosystem can significantly influence ecosystem dynamics, and that aerial transport has been identified as an important source of biological input to remote locations. With the considerable effort devoted in recent decades to understanding atmospheric circulation in the south-polar region, a unique opportunity has emerged to investigate the atmospheric ecology of Antarctica, from regional to continental scales. This concept note identifies key questions in Antarctic microbial biogeography and the need for standardized sampling and analysis protocols to address such questions. A consortium of polar aerobiologists is established to bring together researchers with a common interest in the airborne dispersion of microbes and other propagules in the Antarctic, with opportunities for comparative studies in the Arctic
    corecore