1,729 research outputs found

    Trellis decoding complexity of linear block codes

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    In this partially tutorial paper, we examine minimal trellis representations of linear block codes and analyze several measures of trellis complexity: maximum state and edge dimensions, total span length, and total vertices, edges and mergers. We obtain bounds on these complexities as extensions of well-known dimension/length profile (DLP) bounds. Codes meeting these bounds minimize all the complexity measures simultaneously; conversely, a code attaining the bound for total span length, vertices, or edges, must likewise attain it for all the others. We define a notion of “uniform” optimality that embraces different domains of optimization, such as different permutations of a code or different codes with the same parameters, and we give examples of uniformly optimal codes and permutations. We also give some conditions that identify certain cases when no code or permutation can meet the bounds. In addition to DLP-based bounds, we derive new inequalities relating one complexity measure to another, which can be used in conjunction with known bounds on one measure to imply bounds on the others. As an application, we infer new bounds on maximum state and edge complexity and on total vertices and edges from bounds on span lengths

    Towards a Critical Theory of Adult Learning/Education: Transformational Theory and Beyond

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    Given the great promise of critical theory to transform the field of adult education and its understanding of adult learning, indeed, to create, as Mezirow boldly proclaimed two decades ago, a critical theory of adult learning, where are we now

    Building a Shared Understanding of Female Participation in IT through Collaboration: A Shared Mental Model Approach

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    Information Technology has never been more pervasive and accessible, yet decreasing female participation in the field (and the variety of reported causes) presents a ‘wicked problem’ for IT educators and professionals. In this article, we suggest that female students’ decision-making is adversely impacted by an inaccurate, shared understanding of IT. Subsequently, the problem of low female participation in IT requires a practical, collaborative solution. Employing an abductive research approach, we undertook a qualitative, exploratory study of female-only schools in Ireland using the #MakeITWork programme. During this multi-phased programme, we conducted (i) focus groups to explore female students’ perception of IT undergraduate degree programmes and careers; (ii) knowledge exchange (KX) sessions to communicate IT degree and career opportunities; and (iii) a survey to assess the efficacy of the approach in changing perceptions. Data analysis revealed that a new accurate shared mental model (SMM) was needed to support female students’ education decisions. This facilitated theory development with respect to female students’ decision to pursue IT education and careers. Study findings indicate that while attitudes towards IT careers are largely outdated, these views can be changed through a collaborative intervention workshop approach. This can be achieved through greater stakeholder collaboration and better quality information available via novel formats

    Combined Industry, Space and Earth Science Data Compression Workshop

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    The sixth annual Space and Earth Science Data Compression Workshop and the third annual Data Compression Industry Workshop were held as a single combined workshop. The workshop was held April 4, 1996 in Snowbird, Utah in conjunction with the 1996 IEEE Data Compression Conference, which was held at the same location March 31 - April 3, 1996. The Space and Earth Science Data Compression sessions seek to explore opportunities for data compression to enhance the collection, analysis, and retrieval of space and earth science data. Of particular interest is data compression research that is integrated into, or has the potential to be integrated into, a particular space or earth science data information system. Preference is given to data compression research that takes into account the scien- tist's data requirements, and the constraints imposed by the data collection, transmission, distribution and archival systems

    A Call to Arms: Revisiting Database Design

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    Good database design is crucial to obtain a sound, consistent database, and - in turn - good database design methodologies are the best way to achieve the right design. These methodologies are taught to most Computer Science undergraduates, as part of any Introduction to Database class. They can be considered part of the "canon", and indeed, the overall approach to database design has been unchanged for years. Moreover, none of the major database research assessments identify database design as a strategic research direction. Should we conclude that database design is a solved problem? Our thesis is that database design remains a critical unsolved problem. Hence, it should be the subject of more research. Our starting point is the observation that traditional database design is not used in practice - and if it were used it would result in designs that are not well adapted to current environments. In short, database design has failed to keep up with the times. In this paper, we put forth arguments to support our viewpoint, analyze the root causes of this situation and suggest some avenues of research.Comment: Removed spurious column break. Nothing else was change

    Remission vs low disease activity: function, quality of life and structural outcomes in the Early Rheumatoid Arthritis Study and Network

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    Objectives To examine associations between function, quality of life and structural outcomes in patients achieving remission vs low disease activity in early RA. Methods Demographic, clinical and radiographic variables were collected at baseline and then annually from the Early Rheumatoid Arthritis Study (ERAS) and Early Rheumatoid Arthritis Network (ERAN) inception cohorts in routine care from 1986 to 2012. Disease activity was categorized: mean DAS28 score between years 1 and 5: remission [mean remission DAS (mRDAS) <2.6] or low [mean low DAS (mLDAS) 2.6–3.2]; sustained low/remission DAS28 (sLDAS/sRDAS) at years 1 and 2; and sustained Boolean remission (sBR) at years 1 and 2. Changes in HAQ and Short Form 36 Health Survey Questionnaire [SF-36; physical (PCS) and mental (MCS) component score]) and total Sharp van der Heijde (SvdH) scores for each disease activity category were modelled using multi-level models. Covariates included year of onset, age, gender and DMARD use at first visit. Results Of 2701 patients, 562 (21%) were categorized mRDAS, 330 (12%) mLDAS, 279 (10%) sRDAS, 203 (7.5%) sLDAS and 93 (3%) sBR. Patients categorized as mRDAS had increasingly divergent improved HAQ, SF-36 PCS, MCS and total SvdH scores compared with mLDAS (P-values 0.001 to <0.0001, all time points). Patients categorized as sRDAS had better HAQ, SF-36 PCS and MCS scores (P-values 0.05 to <0.0001, all time points) and SvdH scores (P = 0.05, years 3–5) over sLDAS. sBR was associated with better HAQ, and SF-36 PCS and MCS scores over sLDAS (P-values 0.002 to <0.0001, all time points). Conclusion These findings from routine care support ACR/EULAR guidelines that remission is a preferable goal over low disease activity in early RA.Peer reviewedFinal Published versio

    Use and outcomes of targeted therapies in early and metastatic HER2-positive breast cancer in Australia: Protocol detailing observations in a whole of population cohort

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    Background: The management of human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) has changed dramatically with the introduction and widespread use of HER2-targeted therapies. However, there is relatively limited real-world information on patterns of use, effectiveness and safety in whole of population cohorts. The research programme detailed in this protocol will generate evidence on the prescribing patterns, safety monitoring and outcomes of patients with BC treated with HER2- targeted therapies in Australia. Methods/design: Our ongoing research programme will involve a series of retrospective cohort studies that include every patient accessing Commonwealth-funded HER2-targeted therapies for the treatment of early BC and advanced BC in Australia. At the time of writing, our cohorts consist of 11 406 patients with early BC and 5631 with advanced BC who accessed trastuzumab and lapatinib between 2001 and 2014. Pertuzumab and trastuzumab emtansine were publicly funded for metastatic BC in 2015, and future data updates will include patients accessing these medicines. We will use dispensing claims for cancer and other medicines, medical service claims and demographics data for each patient accessing HER2- targeted therapies to undertake this research. Ethics and dissemination: Ethics approval has been granted by the Population Health Service Research Ethics Committee and data access approval has been granted by the Australian Department of Human Services (DHS) External Review Evaluation Committee. Our findings will be reported in peer-reviewed publications, conference presentations and policy forums. By providing detailed information on the use and outcomes associated with HER2-targeted therapies in a national cohort treated in routine clinical care, our research programme will better inform clinicians and patients about the real-world use of these treatments and will assist third-party payers to better understand the use and economic costs of these treatments

    Extended-interval Dosing of Gentamicin for Treatment of Neonatal Sepsis in Developed and Developing Countries

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    Serious bacterial infections are the single most important cause of neonatal mortality in developing countries. Case-fatality rates for neonatal sepsis in developing countries are high, partly because of inadequate administration of necessary antibiotics. For the treatment of neonatal sepsis in resource-poor, high-mortality settings in developing countries where most neonatal deaths occur, simplified treatment regimens are needed. Recommended therapy for neonatal sepsis includes gentamicin, a parenteral aminoglycoside antibiotic, which has excellent activity against gram-negative bacteria, in combination with an antimicrobial with potent gram-positive activity. Traditionally, gentamicin has been administered 2–3 times daily. However, recent evidence suggests that extended-interval (i.e. ≄24 hours) dosing may be applicable to neonates. This review examines the available data from randomized and non-randomized studies of extended-interval dosing of gentamicin in neonates from both developed and developing countries. Available data on the use of gentamicin among neonates suggest that extended dosing intervals and higher doses (>4 mg/kg) confer a favourable pharmacokinetic profile, the potential for enhanced clinical efficacy and decreased toxicity at reduced cost. In conclusion, the following simplified weight-based dosing regimen for the treatment of serious neonatal infections in developing countries is recommended: 13.5 mg (absolute dose) every 24 hours for neonates of ≄2,500 g, 10 mg every 24 hours for neonates of 2,000–2,499 g, and 10 mg every 48 hours for neonates of <2,000 g

    Early disease progression of Hurler syndrome

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    Abstract Background Newborn screening for mucopolysaccharidosis type I (MPS I) shows promise to improve outcomes by facilitating early diagnosis and treatment. However, diagnostic tests for MPS I are of limited value in predicting whether a child will develop severe central nervous system disease associated with Hurler syndrome, or minimal or no central nervous system involvement associated with the attenuated phenotypes (Hurler–Scheie and Scheie syndromes). Given that the optimal treatment differs between Hurler syndrome and the attenuated MPS I phenotypes, the absence of a reliable prognostic biomarker complicates clinical decision making for infants diagnosed through newborn screening. Information about the natural history of Hurler syndrome may aid in the management of affected infants, contribute to treatment decisions, and facilitate evaluation of treatment effectiveness and prognosis. Thus, the aim of this study was to characterize the progression and timing of symptom onset in infants with Hurler syndrome. Results Clinical data from 55 patients evaluated at a single center were retrospectively reviewed. Information about each child’s medical history was obtained following a standardized protocol including a thorough parent interview and the review of previous medical records. All patients underwent systematic physical and neurodevelopmental evaluations by a multidisciplinary team. Nearly all patients (98%) showed signs of disease during the first 6 months of life. Common early disease manifestations included failed newborn hearing screen, respiratory symptoms, difficulty latching, and otitis media. Other symptoms such as kyphosis, corneal clouding, cardiac disease, joint restrictions, and enlarged head circumference typically appeared slightly later (median age, 8–10 months). During the first 12 months, gross motor development was the most severely affected area of functioning, and a significant number of patients also experienced language delays. Cognition was typically preserved during this period. Conclusions In this large cohort of patients with Hurler syndrome, the vast majority showed signs and symptoms of disease during the first months of life. More research is needed to determine the extent to which early clinical manifestations of MPS I can predict phenotype and treatment outcomes
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