469 research outputs found

    Level-Based Analysis of the Population-Based Incremental Learning Algorithm

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    The Population-Based Incremental Learning (PBIL) algorithm uses a convex combination of the current model and the empirical model to construct the next model, which is then sampled to generate offspring. The Univariate Marginal Distribution Algorithm (UMDA) is a special case of the PBIL, where the current model is ignored. Dang and Lehre (GECCO 2015) showed that UMDA can optimise LeadingOnes efficiently. The question still remained open if the PBIL performs equally well. Here, by applying the level-based theorem in addition to Dvoretzky--Kiefer--Wolfowitz inequality, we show that the PBIL optimises function LeadingOnes in expected time O(nλlogλ+n2)\mathcal{O}(n\lambda \log \lambda + n^2) for a population size λ=Ω(logn)\lambda = \Omega(\log n), which matches the bound of the UMDA. Finally, we show that the result carries over to BinVal, giving the fist runtime result for the PBIL on the BinVal problem.Comment: To appea

    Online-based participatory design: A Case Study of Developing International Standards During a Pandemic

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    Standards are essential instruments to ensure the safety, efficiency and quality of products, services, systems, processes, and environments. In pre-pandemic times, standard development process used to happen through in-person consultation and meetings, however, the COVID-19 pandemic disrupted the whole routine. A team of technical experts from the National Standards Authority of Ireland trialled an online-based participatory design process to support the review and development of a standard through stakeholder engagement. This article introduces the experience of developing a new standard by leveraging on emerging digital technologies, through stakeholder participation. This research offers a framework, outlining the steps undertaken during the process, to support future online-based standard development processes in co-operation with stakeholders, by respecting cultures, backgrounds, skills, and experiences

    The liminality of trajectory shifts in institutional entrepreneurship

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    In this paper, we develop a process model of trajectory shifts in institutional entrepreneurship. We focus on the liminal periods experienced by institutional entrepreneurs when they, unlike the rest of the organization, recognize limits in the present and seek to shift a familiar past into an unfamiliar and uncertain future. Such periods involve a situation where the new possible future, not yet fully formed, exists side-by-side with established innovation trajectories. Trajectory shifts are moments of truth for institutional entrepreneurs, but little is known about the underlying mechanisms of how entrepreneurs reflectively deal with liminality to conceive and bring forth new innovation trajectories. Our in-depth case study research at CarCorp traces three such mechanisms (reflective dissension, imaginative projection, and eliminatory exploration) and builds the basis for understanding the liminality of trajectory shifts. The paper offers theoretical implications for the institutional entrepreneurship literature

    The interpersonal processes of non-suicidal self-injury: A systematic review and meta-synthesis

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    Background: Understanding the processes underlying non-suicidal self-injury (NSSI) is important given the negative consequences of this behaviour. Qualitative research has the potential to provide an in-depth exploration of this. There has been limited research regarding the interpersonal processes associated with NSSI; therefore, a meta-synthesis was conducted to investigate this. Methods: A search of PsycINFO, MEDLINE, Web of Science, and CINAHL electronic databases from date of inception to November 2020 was conducted. In total, 30 papers were included in the final review. A meta-ethnographic approach was utilized to synthesize the data. Results: Two overarching themes were found. Within ‘Powerful relational dynamics’, NSSI was cited as a response to participants becoming stuck in aversive or disempowering relational positions with others. Within the ‘Taking matters into their own hands’ subtheme, NSSI was reported as a way for participants to get interpersonal and emotional needs met. Limitations: Several included papers did not comment on the researcher–participant relationship, which may have affected qualitative results. A small number of potentially eligible papers were unavailable for synthesizing. Conclusion: Findings provide a more nuanced investigation of the interpersonal processes underlying NSSI. Consistent with relevant theories, NSSI appears to be a way of mitigating difficult interpersonal experiences or getting interpersonal needs met. NSSI may be engaged in as a substitute to other, less damaging ways to cope. An argument is made for a more empathetic understanding of NSSI and the use of relational interventions. Practitioner points: Self-injury may occur in response to interpersonal stressors Self-injury can be a means to get interpersonal needs met Self-injury may replace other means of coping that become blocked or thwarted Emotional distress can be closely linked with interpersonal factors for this group Relational therapies may be beneficial where interpersonal processes are linked to NSSI

    Non-operative treatment for perforated gastro-duodenal peptic ulcer in Duchenne Muscular Dystrophy: a case report

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    BACKGROUND: Clinical characteristics and complications of Duchenne muscular dystrophy caused by skeletal and cardiac muscle degeneration are well known. Gastro-intestinal involvement has also been recognised in these patients. However an acute perforated gastro-duodenal peptic ulcer has not been documented up to now. CASE PRESENTATION: A 26-year-old male with Duchenne muscular dystrophy with a clinical and radiographic diagnosis of acute perforated gastro-duodenal peptic ulcer is treated non-operatively with naso-gastric suction and intravenous medication. Gastrointestinal involvement in Duchenne muscular dystrophy and therapeutic considerations in a high risk patient are discussed. CONCLUSION: Non-surgical treatment for perforated gastro-duodenal peptic ulcer should be considered in high risk patients, as is the case in patients with Duchenne muscular dystrophy. Patients must be carefully observed and operated on if non-operative treatment is unsuccessful

    Odontoid metastasis: a potential lethal complication

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    Nearly one third of cervical spine metastasis has a primary breast malignancy. Patients with cervical metastasis have higher mortality due to advanced stage of the malignancy. Treatment is palliative to relieve pain, prevent pathological fracture, improve mobility and function, and prolong survival. We describe a 40-year-old woman with a history of breast cancer who presented with neck and shoulder pain of 1 week duration with no neurological deficit. Following clinical examination, radiographs taken of the cervical spine was normal. Radiographs repeated 3 weeks later revealed a large lytic lesion of the odontoid occupying 70–80% of the peg. Further investigation including magnetic resonance imaging and bone scan showed no further spinal lesions. She underwent cyclical radiotherapy with complete resolution of the odontoid peg lesion and clinically was asymptomatic at 2 years. Metastatic lesions of the odontoid are atypical, and this case reinforces the necessity of early detection to evade disastrous consequences

    Comparison of prognostic scores and surgical approaches to treat spinal metastatic tumors: A review of 57 cases

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    Surgical treatment of metastatic spinal cord compression with or without neural deficit is controversial. Karnofsky and Tokuhashi scores have been proposed for prognosis of spinal metastasis. Here, we conducted a retrospective analysis of Karnofsky and modified Tokuhashi scores in 57 consecutive patients undergoing surgery for secondary spinal metastases to evaluate the value of these scores in aiding decision making for surgery. Comparison of preoperative Karnofsky and modified Tokuhashi scores with the type of the surgical approach for each patient revealed that both scores not only reliably estimate life expectancy, but also objectively improved surgical decisions. When the general status of the patient is poor (i.e., Karnofsky score less than 40% or modified Tokuhashi score of 5 or greater), palliative treatments and radiotherapy, rather than surgery, should be considered

    Epitope-positive truncating MLH1 mutation and loss of PMS2: implications for IHC-directed genetic testing for lynch syndrome

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    We assessed mismatch repair by immunohistochemistry (IHC) and microsatellite instability (MSI) analysis in an early onset endometrial cancer and a sister’s colon cancer. We demonstrated high-level MSI and normal expression for MLH1, MSH2 and MSH6. PMS2 failed to stain in both tumors, strongly implicating a PMS2 defect. This family did not meet clinical criteria for Lynch syndrome. However, early onset endometrial cancers in the proband and her sister, a metachronous colorectal cancer in the sister as well as MSI in endometrial and colonic tumors suggested a heritable mismatch repair defect. PCR-based direct exonic sequencing and multiplex ligation-dependent probe amplification (MLPA) were undertaken to search for PMS2 mutations in the germline DNA from the proband and her sister. No mutation was identified in the PMS2 gene. However, PMS2 exons 3, 4, 13, 14, 15 were not evaluated by MLPA and as such, rearrangements involving those exons cannot be excluded. Clinical testing for MLH1 and MSH2 mutation revealed a germline deletion of MLH1 exons 14 and 15. This MLH1 germline deletion leads to an immunodetectable stable C-terminal truncated MLH1 protein which based on the IHC staining must abrogate PMS2 stabilization. To the best of our knowledge, loss of PMS2 in MLH1 truncating mutation carriers that express MLH1 in their tumors has not been previously reported. This family points to a potential limitation of IHC-directed gene testing for suspected Lynch syndrome and the need to consider comprehensive MLH1 testing for individuals whose tumors lack PMS2 but for whom PMS2 mutations are not identified

    A distributed beam loss monitor for the Australian Synchrotron

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    © 2018 Elsevier B.V. A distributed beam loss monitoring system, named the optical fibre Beam Loss Monitor, has been installed at the Australian Synchrotron. Relativistic charged particles produced in beam loss events generate photons via the Cherenkov mechanism in four silica fibres that run parallel to the beam pipe and cover the majority of the accelerator's length. These photons are then guided by the fibres to detectors located outside of the accelerator tunnel. By measuring the time of flight of these photons, the locations of beam losses can be reconstructed. Based on this method a calibration was produced, mapping the time of flight to a position along the accelerator. This calibration was applied to loss signals collected on the first pass of the beam through the accelerator and the locations of prominent losses were determined. Using this system it was possible to investigate the effect, on the location and intensity of losses, in response to changes in the lattice parameters on a shot-by-shot basis. This system is now used in routine operations and has resulted in a 40 % increase in the capture efficiency of the booster ring

    Automatic Robust Neurite Detection and Morphological Analysis of Neuronal Cell Cultures in High-content Screening

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    Cell-based high content screening (HCS) is becoming an important and increasingly favored approach in therapeutic drug discovery and functional genomics. In HCS, changes in cellular morphology and biomarker distributions provide an information-rich profile of cellular responses to experimental treatments such as small molecules or gene knockdown probes. One obstacle that currently exists with such cell-based assays is the availability of image processing algorithms that are capable of reliably and automatically analyzing large HCS image sets. HCS images of primary neuronal cell cultures are particularly challenging to analyze due to complex cellular morphology. Here we present a robust method for quantifying and statistically analyzing the morphology of neuronal cells in HCS images. The major advantages of our method over existing software lie in its capability to correct non-uniform illumination using the contrast-limited adaptive histogram equalization method; segment neuromeres using Gabor-wavelet texture analysis; and detect faint neurites by a novel phase-based neurite extraction algorithm that is invariant to changes in illumination and contrast and can accurately localize neurites. Our method was successfully applied to analyze a large HCS image set generated in a morphology screen for polyglutaminemediated neuronal toxicity using primary neuronal cell cultures derived from embryos of a Drosophila Huntington’s Disease (HD) model.National Institutes of Health (U.S.) (Grant
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