884 research outputs found

    Discovering Restricted Regular Expressions with Interleaving

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    Discovering a concise schema from given XML documents is an important problem in XML applications. In this paper, we focus on the problem of learning an unordered schema from a given set of XML examples, which is actually a problem of learning a restricted regular expression with interleaving using positive example strings. Schemas with interleaving could present meaningful knowledge that cannot be disclosed by previous inference techniques. Moreover, inference of the minimal schema with interleaving is challenging. The problem of finding a minimal schema with interleaving is shown to be NP-hard. Therefore, we develop an approximation algorithm and a heuristic solution to tackle the problem using techniques different from known inference algorithms. We do experiments on real-world data sets to demonstrate the effectiveness of our approaches. Our heuristic algorithm is shown to produce results that are very close to optimal.Comment: 12 page

    Radiomics to better characterize small renal masses

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    Purpose: Radiomics is a specific field of medical research that uses programmable recognition tools to extract objective information from standard images to combine with clinical data, with the aim of improving diagnostic, prognostic, and predictive accuracy beyond standard visual interpretation. We performed a narrative review of radiomic applications that may support improved characterization of small renal masses (SRM). The main focus of the review was to identify and discuss methods which may accurately differentiate benign from malignant renal masses, specifically between renal cell carcinoma (RCC) subtypes and from angiomyolipoma without visible fat (fat-poor AML) and oncocytoma. Furthermore, prediction of grade, sarcomatoid features, and gene mutations would be of importance in terms of potential clinical utility in prognostic stratification and selecting personalised patient management strategies. / Methods: A detailed search of original articles was performed using the PubMed–MEDLINE database until 20 September 2020 to identify the English literature relevant to radiomics applications in renal tumour assessment. In total, 42 articles were included in the analysis in 3 main categories related to SRM: prediction of benign versus malignant SRM, subtypes, and nuclear grade, and other features of aggressiveness. / Conclusion: Overall, studies reported the superiority of radiomics over expert radiological assessment, but were mainly of retrospective design and therefore of low-quality evidence. However, it is clear that radiomics is an attractive modality that has the potential to improve the non-invasive diagnostic accuracy of SRM imaging and prediction of its natural behaviour. Further prospective validation studies of radiomics are needed to augment management algorithms of SRM

    Influence of prior knowledge on eye movements to scenes as revealed by hidden Markov models.

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    Human visual experience usually provides ample opportunity to accumulate knowledge about events unfolding in the environment. In typical scene perception experiments, however, participants view images that are unrelated to each other and, therefore, they cannot accumulate knowledge relevant to the upcoming visual input. Consequently, the influence of such knowledge on how this input is processed remains underexplored. Here, we investigated this influence in the context of gaze control. We used sequences of static film frames arranged in a way that allowed us to compare eye movements to identical frames between two groups: a group that accumulated prior knowledge relevant to the situations depicted in these frames and a group that did not. We used a machine learning approach based on hidden Markov models fitted to individual scanpaths to demonstrate that the gaze patterns from the two groups differed systematically and, thereby, showed that recently accumulated prior knowledge contributes to gaze control. Next, we leveraged the interpretability of hidden Markov models to characterize these differences. Additionally, we report two unexpected and interesting caveats of our approach. Overall, our results highlight the importance of recently acquired prior knowledge for oculomotor control and the potential of hidden Markov models as a tool for investigating it

    Prior knowledge about events depicted in scenes decreases oculomotor exploration.

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    The visual input that the eyes receive usually contains temporally continuous information about unfolding events. Therefore, humans can accumulate knowledge about their current environment. Typical studies on scene perception, however, involve presenting multiple unrelated images and thereby render this accumulation unnecessary. Our study, instead, facilitated it and explored its effects. Specifically, we investigated how recently-accumulated prior knowledge affects gaze behavior. Participants viewed sequences of static film frames that contained several 'context frames' followed by a 'critical frame'. The context frames showed either events from which the situation depicted in the critical frame naturally followed, or events unrelated to this situation. Therefore, participants viewed identical critical frames while possessing prior knowledge that was either relevant or irrelevant to the frames' content. In the former case, participants' gaze behavior was slightly more exploratory, as revealed by seven gaze characteristics we analyzed. This result demonstrates that recently-gained prior knowledge reduces exploratory eye movements

    Cytoreductive nephrectomy in the current treatment algorithm

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    The two recent prospective randomized trials CARMENA and SURTIME have changed the therapy paradigm of metastatic renal cell carcinoma. The CARMENA trial was conducted to investigate whether cytoreductive nephrectomy (CN) is required in the targeted therapy area, whereas SURTIME studied whether deferred CN in combination with sunitinib can be used to identify patients with inherent targeted therapy resistance. In the current review, we provide a comprehensive discussion of two randomized studies and the current evidence with up-do-date algorithms for treating primary metastatic clear-cell renal cell carcinoma in the era of targeted therapy and immune-checkpoint inhibition

    Multifractal analysis of perceptron learning with errors

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    Random input patterns induce a partition of the coupling space of a perceptron into cells labeled by their output sequences. Learning some data with a maximal error rate leads to clusters of neighboring cells. By analyzing the internal structure of these clusters with the formalism of multifractals, we can handle different storage and generalization tasks for lazy students and absent-minded teachers within one unified approach. The results also allow some conclusions on the spatial distribution of cells.Comment: 11 pages, RevTex, 3 eps figures, version to be published in Phys. Rev. E 01Jan9

    Make movement your mission: evaluation of an online digital health initiative to increase physical activity in older people during the COVID-19 pandemic

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    OBJECTIVE: To formatively evaluate the Make Movement Your Mission (MMYM) digital health initiative to promote physical activity (PA) levels and help avert the negative consequences of sedentary behaviours in older adults during the SARS-CoV2 pandemic. METHODS: Mixed-method study to explore activity levels, changes in physical function and Activities of Daily Living (ADLs), quality-of-life, social engagement, technology use, and accessibility. Survey data were analysed descriptively. Qualitative interviews were analysed using framework analysis. RESULTS: Forty-one respondents completed the survey (Mean age 68.4 (8.9) years; 34 Female), 68% aged ≄ 65 years. Average attendance was 14.3 sessions per week (3.5 h). 73% had been with MMYM for >1 year, 90% reported they were engaging in more movement on a typical day, and 75% reported improvement in ability to perform moderate PA. Since starting MMYM, participation in activities targeting strength, balance and flexibility increased (by 48%, 73% and 75%, respectively). 83% met strength and 90% balance PA guidelines for health (≄ 2x per week). Between 18% and 53% of respondents reported improvements in ADLs, 53% reported better quality-of-life, and 28% increased use of the internet. Eight participants were interviewed (Mean age 70.7 (6.7) years; 7 Female). Activity levels were promoted by having direct support from the instructor through Facebook messages pre and post live sessions, having group expectation about quality and level of engagement, having a sense of control and encouragement from others, MMYMs regularity, choice around level of engagement and accessibility. Noticing short-term outcomes in balance and posture helped boost confidence and continued participation. CONCLUSION: Clinical trials need to robustly assess its effectiveness and acceptability

    The adjuvant treatment of kidney cancer: a multidisciplinary outlook

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    Approximately 70% of cases of kidney cancer are localized or locally advanced at diagnosis. Among patients who undergo surgery for these cancers, 30–35% will eventually develop potentially fatal metachronous distant metastases. Effective adjuvant treatments are urgently needed to reduce the risk of recurrence of kidney cancer and of dying of metastatic disease. To date, almost all of the tested adjuvant agents have failed to demonstrate any benefit. Only two trials of an autologous renal tumour cell vaccine and of the vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor sunitinib have shown positive results, but these have been criticized for methodological reasons and conflicting data, respectively. The results of two additional trials of targeted agents as adjuvant therapies have not yet been published. Novel immune checkpoint inhibitors are promising approaches to adjuvant therapy in kidney cancer, and a number of trials are now underway. An important component of the management of patients with kidney cancer, particularly those who undergo radical resection for localized renal cell carcinoma, is the preservation of kidney function to reduce morbidity and mortality. The optimal management of these patients therefore requires a multidisciplinary approach involving nephrologists, oncologists, urologists and pathologists

    Safety and feasibility of early single-dose mitomycin C bladder instillation after robot-assisted radical nephroureterectomy

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    Objectives: To assess the safety and feasibility of early single‐dose mitomycin C (MMC) bladder instillation after robot‐assisted radical nephroureterectomy (RARNU) at a tertiary kidney cancer centre. RARNU with bladder cuff excision and subsequent MMC bladder instillation to reduce recurrence risk is the ‘gold standard’ for high‐risk upper urinary tract urothelial carcinoma (UUTUC). We adapted a RARNU technique with precise distal ureteric dissection, bladder cuff excision and watertight bladder closure. Patients and Methods: We retrospectively reviewed all patients undergoing RARNU for UUTUC at our centre performed as a standardised transperitoneal procedure comprising of: bladder cuff excision, two‐layer watertight closure and intraoperative bladder leak test; without re‐docking/re‐positioning of the robotic surgical system. Patient demographics, the timing of MMC instillation, adverse events (surgical and potentially MMC‐related) and length of stay (LOS) were assessed according to the Clavien–Dindo classification. Results: A total of 69 patients underwent a RARNU with instillation of MMC. The median (interquartile range [IQR]) age was 70 (62–78) years. The median (IQR) day of MMC instillation was 2 (1–3) days and the median (IQR) LOS was 2 (2–4) days, with urethral catheter removal on day of discharge in all cases. Only Grade I Clavien–Dindo complications occurred in seven patients (10%); five had ileus, one a wound infection and one a self‐limiting delirium, all managed conservatively. No adverse events potentially related to MMC instillation were noted within 30 days postoperatively. Conclusion: The use of intravesical MMC instillation given in the immediate postoperative period appears feasible and safe in patients undergoing RARNU with intraoperative confirmation of a water‐tight closure ensuring early catheter‐free discharge, with no significant adverse events. The potential reduction in intravesical recurrence in patients receiving early MMC needs to be assessed with longitudinal follow‐up studies
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