1,067 research outputs found

    Some Results on the Boundary Control of Systems of Conservation Laws

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    This note is concerned with the study of the initial boundary value problem for systems of conservation laws from the point of view of control theory, where the initial data is fixed and the boundary data are regarded as control functions. We first consider the problem of controllability at a fixed time for genuinely nonlinear Temple class systems, and present a description of the set of attainable configurations of the corresponding solutions in terms of suitable Oleinik-type estimates. We next present a result concerning the asymptotic stabilization near a constant state for general nĂ—nn\times n systems. Finally we show with an example that in general one cannot achieve exact controllability to a constant state in finite time.Comment: 10 pages, 4 figures, conferenc

    Real-time workload classification during driving using hyperNetworks

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    Classifying human cognitive states from behavioral and physiological signals is a challenging problem with important applications in robotics. The problem is challenging due to the data variability among individual users, and sensor artifacts. In this work, we propose an end-to-end framework for real-time cognitive workload classification with mixture Hyper Long Short Term Memory Networks (m-HyperLSTM), a novel variant of HyperNetworks. Evaluating the proposed approach on an eye-gaze pattern dataset collected from simulated driving scenarios of different cognitive demands, we show that the proposed framework outperforms previous baseline methods and achieves 83.9% precision and 87.8% recall during test. We also demonstrate the merit of our proposed architecture by showing improved performance over other LSTM-based method

    Random Expert Distillation: Imitation Learning via Expert Policy Support Estimation

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    We consider the problem of imitation learning from a finite set of expert trajectories, without access to reinforcement signals. The classical approach of extracting the expert's reward function via inverse reinforcement learning, followed by reinforcement learning is indirect and may be computationally expensive. Recent generative adversarial methods based on matching the policy distribution between the expert and the agent could be unstable during training. We propose a new framework for imitation learning by estimating the support of the expert policy to compute a fixed reward function, which allows us to re-frame imitation learning within the standard reinforcement learning setting. We demonstrate the efficacy of our reward function on both discrete and continuous domains, achieving comparable or better performance than the state of the art under different reinforcement learning algorithms

    Obstetrics and Gynecology Emergency Department Activity during Lockdown in a Teaching Hospital, Hub Center, for COVID-19

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    Background. The lockdown related to the SARS-CoV-2 pandemic has imposed profound changes in the interaction of the population with hospitals and emergency departments. The main aim of this research was to evaluate the impact of lockdown on the activity of obstetrics and gynecology emergency department (OGED) in a teaching hospital, hub center, for COVID-19. Methods. The study considers all visits to the OGED with their different triage color codes that represent the clinical severity of each case (from the most severe to the least one: red, yellow, green, white). Data were selected through the "PSNet"triage program and collected anonymously. We analyzed frequency distributions of the variables separately for each woman and calculated mean and standard deviations for continuous variables. We then analyzed the association between factors and outcomes for categorical variables (expressed as a number and percentage of the total) using the chi-square test (χ2). The level of significance was established with p<0.05. Statistical analysis was performed using SPSS Statistics V20.0. Given the fact that the study has a retrospective observational nature and it is based on an anonymous routine database, approval by the Local Ethics Committee was not necessary. Results. The relative decrease of patients presenting to OGED in 2020 was -50.96%. The percentage of nonpregnant women was significantly lower in 2020 compared to 2019 (p≤0.0001; Δ = -79.46%). Regarding the obstetric group, we saw an important decrease of visits in 2020 compared to 2019 (p<0.0001; Δ = -40%). The prevalence of yellow codes was significantly higher in 2020 (Δ = +29.72%), while that of white (Δ = -61.58%) and green (Δ = -52.22%) codes was significantly lower (p≤0.0001). Comparing the diagnoses at discharge, we could highlight significant reductions in 2020 for more than one diagnosis: bleeding (p≤0.0001; Δ = -70.42%), pain (p≤0.0001; Δ = -81.22%), urinary diseases (p=0.004; Δ = -75.64%), and gastrointestinal diseases (p≤0.0001; Δ = -87.50%). Conclusions. An evident change emerged in relation to the dynamics between the local obstetrical and gynecological population, and OGED resources. The COVID-19 lockdown greatly reduced the rate of admission to OGED without time-related obstetric and gynecological complications. The reduction of admissions suggests a more appropriate use of the ED by patients that may inspire future policies for the implementation of emergency services

    A new emerging oral infection: Raoultella planticola in a boy with haematological malignancy

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    BACKGROUND: Oral mucositis is a common complication in pediatric cancer patients, affecting up to 80% of children. Due to neutropenia and disruption of the mucosal barrier, chemotherapy-induced oral mucositis is often complicated by super-infections. CASE REPORT: A 16-years old male with stage 3 Burkitt's lymphoma developed chemotherapy induced oral mucositis grade 3 (according to WHO scale). Ulcers were quickly growing (reaching a maximum diameter of 3 cm) and became greyish in colour, resulting in dysphagia and pain. A swab of the lesions was taken and microbiological tests were performed. The sample grew for Raoultella planticola, an encapsulated Gram-negative bacterium whose full pathogenic potential still needs to be defined. TREATMENT: The patient received antibiotic combination therapy with Amikacin and Ceftazidime for 8 days. Complete healing of the lesions and resolution of the symptoms were reached and he completed his antineoplastic therapy without further complications. FOLLOW-UP: Twelve months after the infection, he is alive and well, with no oral complaints. CONCLUSION: This is the first report of a Raoultella planticola infection in a patient with chemotherapy induced oral mucositis. This type of infection must be added to the list of organisms to be considered when caring for these patients

    Genetic Features of Metachronous Esophageal Cancer Developed in Hodgkin's Lymphoma or Breast Cancer Long-Term Survivors: An Exploratory Study.

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    Background Development of novel therapeutic drugs and regimens for cancer treatment has led to improvements in patient long-term survival. This success has, however, been accompanied by the increased occurrence of second primary cancers. Indeed, patients who received regional radiotherapy for Hodgkin's Lymphoma (HL) or breast cancer may develop, many years later, a solid metachronous tumor in the irradiated field. Despite extensive epidemiological studies, little information is available on the genetic changes involved in the pathogenesis of these solid therapy-related neoplasms. Methods Using microsatellite markers located in 7 chromosomal regions frequently deleted in sporadic esophageal cancer, we investigated loss of heterozygosity (LOH) and microsatellite instability (MSI) in 46 paired (normal and tumor) samples. Twenty samples were of esophageal carcinoma developed in HL or breast cancer long-term survivors: 14 squamous cell carcinomas (ESCC) and 6 adenocarcinomas (EADC), while 26 samples, used as control, were of sporadic esophageal cancer (15 ESCC and 11 EADC). Results We found that, though the overall LOH frequency at the studied chromosomal regions was similar among metachronous and sporadic tumors, the latter exhibited a statistically different higher LOH frequency at 17q21.31 (p = 0.018). By stratifying for tumor histotype we observed that LOH at 3p24.1, 5q11.2 and 9p21.3 were more frequent in ESCC than in EADC suggesting a different role of the genetic determinants located nearby these regions in the development of the two esophageal cancer histotypes. Conclusions Altogether, our results strengthen the genetic diversity among ESCC and EADC whether they occurred spontaneously or after therapeutic treatments. The presence of histotype-specific alterations in esophageal carcinoma arisen in HL or breast cancer long-term survivors suggests that their transformation process, though the putative different etiological origin, may retrace sporadic ESCC and EADC carcinogenesis

    Idiopathic thrombocytopenic purpura: current concepts in pathophysiology and management.

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    Idiopathic thrombocytopenic purpura (ITP) is characterized by a low platelet count, which is the result of both increased pla- telet destruction and insufficient platelet production. Although the development of autoantibodies against platelet glycoproteins remains central in the pathophysiology of ITP, several abnormalities involving the cellular mechanisms of immune modu- lation have been identified. Conventional treatments for ITP aim at reducing platelet destruction, either by immunosuppression or splenectomy. Two new thrombopoietic agents,AMG 531 and eltrombopag, have been used in clinical trials to stimulate platelet production in ITP patients not responsive to standard treatments. These new molecules bear no structural resemblance to thrombopoietin, but still bind and activate the thrombopoietin receptor. This review will focus on the pathophysiology and treatment of ITP in adults, highlighting recent advances in both fields
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