1,073 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

    An Integro-Differential Conservation Law arising in a Model of Granular Flow

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    We study a scalar integro-differential conservation law. The equation was first derived in [2] as the slow erosion limit of granular flow. Considering a set of more general erosion functions, we study the initial boundary value problem for which one can not adapt the standard theory of conservation laws. We construct approximate solutions with a fractional step method, by recomputing the integral term at each time step. A-priori L^\infty bounds and BV estimates yield convergence and global existence of BV solutions. Furthermore, we present a well-posedness analysis, showing that the solutions are stable in L^1 with respect to the initial data


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    Objective: The information of safety of antineoplastic agents derives solely from clinical studies that have a number of limitations, such as the number of patients enrolled, selected case studies, follow-up of short duration; therefore, it is not possible to identify the complete profile of safety and possible side effects of the drugs under study. ADRs monitoring and reporting programmes aim to identifying and quantifying the risks associated with the use of drugs provided in a hospital setting. The main objectives of this study were to evaluate the ADRs that occurred during hospitalization for chemotherapy in 7 cancer centers, and to facilitate the development of a monitoring system of pharmacovigilance. Methods: An observational study was conducted in 7 cancer centers in the Emilia Romagna region over a period of 2 years, from January 2012 to January 2014. This study was based on an analysis of ADRs reported. Several parameters were utilised in the data evaluation, including drug and reaction characteristics. Results: From January 2012 to January 2014 No. 884 ADRs were included in National Network of pharmacovigilance. The highest ADR rate (57.4%) was found in the adultĂ‚ females with a mean age of 62. The oncology drug most frequently reported were taxanes and platinum derivates. Conclusion: The results obtained will contribute to the development of strategies for the pharmacovigilance service in 7 cancer centers, which will improve the quality of ADR reporting and ensure safer oncology drug use

    Holomorphic transforms with application to affine processes

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    In a rather general setting of It\^o-L\'evy processes we study a class of transforms (Fourier for example) of the state variable of a process which are holomorphic in some disc around time zero in the complex plane. We show that such transforms are related to a system of analytic vectors for the generator of the process, and we state conditions which allow for holomorphic extension of these transforms into a strip which contains the positive real axis. Based on these extensions we develop a functional series expansion of these transforms in terms of the constituents of the generator. As application, we show that for multidimensional affine It\^o-L\'evy processes with state dependent jump part the Fourier transform is holomorphic in a time strip under some stationarity conditions, and give log-affine series representations for the transform.Comment: 30 page

    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

    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
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